user11541: I came to know about Buddhism very late in my life. It is the time for me to relearn the fundamentals of life. But I struggle with everyday activity. I lack energy.  In fact I have a diabetes. My past Karma has been bad enough to get me a disease. 
My question is: How can Buddhism help me get rid of this disease? If I fix my Karma then will the suffering due to the disease will disappear ? If yes, how can I repent and to whom ?

user471: Let me add on to rob_mtl's good answer.
Firstly, diabetes type 2 is a disease that seems to be reversible and curable by changing one's diet to have less carbohydrates and to be replaced with more fats and proteins. Please see this YouTube TED talk. Interestingly, the Buddha gave similar advice to King Pasenadi of Kosala 2500 years ago, in the Donapaka Sutta, at least with regard to reducing carbohydrate intake. Sometimes, Buddhist teachings can be very down-to-earth and practical.
A similar question to your's, was asked by householder Nakulapita to the Buddha in the Nakulapita Sutta:

I have heard that on one occasion the Blessed One was living among the
  Bhaggas at Crocodile Haunt in the Bhesakala Grove at the Deer Park.
  Then the householder Nakulapita went to the Blessed One and on
  arrival, having bowed down to him, sat to one side. As he was sitting
  there he said to the Blessed One, "Lord, I am a feeble old man, aged,
  advanced in years, having come to the last stage of life. I am
  afflicted in body & ailing with every moment. And it is only rarely
  that I get to see the Blessed One & the monks who nourish the heart.
  May the Blessed One teach me, may the Blessed One instruct me, for my
  long-term benefit & happiness."
"So it is, householder. So it is. The body is afflicted, weak, &
  encumbered. For who, looking after this body, would claim even a
  moment of true health, except through sheer foolishness? So you should
  train yourself: 'Even though I may be afflicted in body, my mind will
  be unafflicted.' That is how you should train yourself."

Later, householder Nakulapita got more detailed advice from Ven. Sariputta the Arahant, elaborating the Buddha's advice:

Ven. Sariputta said: "Now, how is one afflicted in body & afflicted in
  mind?
"There is the case where an uninstructed, run-of-the-mill person — who
  has no regard for noble ones, is not well-versed or disciplined in
  their Dhamma; who has no regard for men of integrity, is not
  well-versed or disciplined in their Dhamma — assumes form (the body)
  to be the self, or the self as possessing form, or form as in the
  self, or the self as in form. He is seized with the idea that 'I am
  form' or 'Form is mine.' As he is seized with these ideas, his form
  changes & alters, and he falls into sorrow, lamentation, pain,
  distress, & despair over its change & alteration.
"He assumes feeling to be the self, or the self as possessing feeling,
  or feeling as in the self, or the self as in feeling. He is seized
  with the idea that 'I am feeling' or 'Feeling is mine.' As he is
  seized with these ideas, his feeling changes & alters, and he falls
  into sorrow, lamentation, pain, distress, & despair over its change &
  alteration.
"He assumes perception to be the self, or the self as possessing
  perception, or perception as in the self, or the self as in
  perception. He is seized with the idea that 'I am perception' or
  'Perception is mine.' As he is seized with these ideas, his perception
  changes & alters, and he falls into sorrow, lamentation, pain,
  distress, & despair over its change & alteration.
"He assumes (mental) fabrications to be the self, or the self as
  possessing fabrications, or fabrications as in the self, or the self
  as in fabrications. He is seized with the idea that 'I am
  fabrications' or 'Fabrications are mine.' As he is seized with these
  ideas, his fabrications change & alter, and he falls into sorrow,
  lamentation, pain, distress, & despair over their change & alteration.
"He assumes consciousness to be the self, or the self as possessing
  consciousness, or consciousness as in the self, or the self as in
  consciousness. He is seized with the idea that 'I am consciousness' or
  'Consciousness is mine.' As he is seized with these ideas, his
  consciousness changes & alters, and he falls into sorrow, lamentation,
  pain, distress, & despair over its change & alteration.
"This, householder, is how one is afflicted in body and afflicted in
  mind.
"And how is one afflicted in body but unafflicted in mind? There is
  the case where a well-instructed disciple of the noble ones — who has
  regard for noble ones, is well-versed & disciplined in their Dhamma;
  who has regard for men of integrity, is well-versed & disciplined in
  their Dhamma — does not assume form to be the self, or the self as
  possessing form, or form as in the self, or the self as in form. He is
  not seized with the idea that 'I am form' or 'Form is mine.' As he is
  not seized with these ideas, his form changes & alters, but he does
  not fall into sorrow, lamentation, pain, distress, or despair over its
  change & alteration.
"He does not assume feeling to be the self...
"He does not assume perception to be the self...
"He does not assume fabrications to be the self...
"He does not assume consciousness to be the self, or the self as
  possessing consciousness, or consciousness as in the self, or the self
  as in consciousness. He is not seized with the idea that 'I am
  consciousness' or 'Consciousness is mine.' As he is not seized with
  these ideas, his consciousness changes & alters, but he does not fall
  into sorrow, lamentation, pain, distress, or despair over its change &
  alteration.
"This, householder, is how one is afflicted in body but unafflicted in
  mind."

Another interesting parable is that of the salt crystal. From the Lonaphala Sutta:

"Suppose that a man were to drop a salt crystal into a small amount of
  water in a cup. What do you think? Would the water in the cup become
  salty because of the salt crystal, and unfit to drink?"
"Yes, lord. Why is that? There being only a small amount of water in
  the cup, it would become salty because of the salt crystal, and unfit
  to drink."
"Now suppose that a man were to drop a salt crystal into the River
  Ganges. What do you think? Would the water in the River Ganges become
  salty because of the salt crystal, and unfit to drink?"
"No, lord. Why is that? There being a great mass of water in the River
  Ganges, it would not become salty because of the salt crystal or unfit
  to drink."
"In the same way, there is the case where a trifling evil deed done by
  one individual [the first] takes him to hell; and there is the case
  where the very same sort of trifling deed done by the other individual
  is experienced in the here & now, and for the most part barely appears
  for a moment.
'Now, a trifling evil act done by what sort of individual takes him to
  hell? There is the case where a certain individual is undeveloped in
  the body, undeveloped in virtue, undeveloped in mind [i.e.,
  painful feelings can invade the mind and stay there], undeveloped in
  discernment: restricted, small-hearted, dwelling with suffering.   A
  trifling evil act done by this sort of individual takes him to hell.
'Now, a trifling evil act done by what sort of individual is
  experienced in the here & now, and for the most part barely appears
  for a moment? There is the case where a certain individual is
  developed in the body, developed in virtue, developed in mind
  [i.e., painful feelings cannot invade the mind and stay there],
  developed in discernment: unrestricted, large-hearted, dwelling with
  the immeasurable. A trifling evil act done by this sort of individual
  is experienced in the here & now, and for the most part barely appears
  for a moment.

For a detailed discussion, please read "Kamma and the Ending of Kamma", by Thanissaro Bhikkhu.

user10967: I thought to answer and hope you will find some useful trough my answer. I also have same conditions similar to yours. I would mention some characteristics about you and you can respond if I am wrong. you are thinking so fast and continuously about metaphysics like your life after death and so on....you possess some IQ more than average person. So my friend above will lead you more stressful conditions as thinking need more and more energy. I am not aware about your family conditions but be little relaxed,gentle,save some energy and maintain harmony with nature. Your intensive curiosity will make you sick. My suggestion to you is maintain your health well and leave the stress and avoid over-thinking. Don't cross your capacity without practice. Get help from others. If you have opportunity to practice "Zen" might help you. To your question "can Buddhism help to overcome physical pain?" Yes master the fundamentals of Buddhism and stick to basics. reach the path step by step. you can't skip the steps mean you waste energy and you will lack of it. Keep away thinking of your past karma aside.you can't do anything about it. Focus on present and control over thinking,get proper medicine, get gentle approach to life, stay healthy. Never forget "Health is the great noble gain in life (Arogyama parama laba) as Budda mentioned. This is the most practical solution for our lives. hope this will help you .Thanks and Metta!

user4900: I don't know your situation and haven't suffered anything like it, so any advice I have may mean nothing to you, but I will say these things:

Karma is the fruit of past action. Don't concern yourself with what's past, and focus on the actions you do in the present. The Buddha said that speculating about the workings of karma is a waste of time, because it is too complex, and (at best) only fully-enlightened beings can see the full chain of causes and effects that led us to where we are now, or where we will go in the future. Kindness and mindfulness in the present moment are our tools to create good karma. Taking care of your health is a part of kindness and mindfulness, because it is important to be kind and forgiving to yourself. If you condemn or harm yourself, you are condemning and harming a future being, so be kind to yourself.
Practicing the Dharma and ending suffering are long-term projects. You may not be able to cure the disease. But every moment of kindness and mindfulness erases a moment of future suffering. Repent to yourself first. If, as you do this, you're moved to repent or ask forgiveness from someone else, then do that, but don't put more pressure on yourself than the disease is already putting on you. Be kind to yourself.
Look at the body in a moment-by-moment way and watch the way energy and pain and sensation change in every single millisecond. Watch how feelings that you think last for minutes, days, or hours are actually fluctuating in every moment. Sometimes there are eruptions of pleasant in the middle of a painful feeling. Different parts of the body are feeling different sensations and energies at different moments. Karma doesn't just act on your life, but also on every single moment within your life- the truth is, you die and are reborn many times a second. Observe the bodily sensations as much as you can.
You will be low on energy, and so practice will be difficult. Forgive yourself for not being a great practitioner, and only do the best you are able to. Look into the mind and see if you can find that little part of your mind that's always fully alert, always watching itself, even when you feel that you're tired and your attention is weak. Use that part of your mind to watch the rest of your body and mind and know that none of it is "you" or "yours".
Disease and physical health are partly the result of karma, but also partly the result of the nature of being human in a world made of matter. To be born human is to be born with a body subject to disease and death. So don't blame yourself for what's part of your nature as a human being. To be born human also means being born to hear the Dharma and to be free to act kindly and mindfully in ways that will improve your future. The fact that your karma led to a human birth means that your past included more positive karmic influences than negative ones. So be kind to yourself.

May you be well.

11541: <p>I came to know about Buddhism very late in my life. It is the time for me to relearn the fundamentals of life. But I struggle with everyday activity. I lack energy.  In fact I have a diabetes. My past Karma has been bad enough to get me a disease. </p>

<p>My question is: How can Buddhism help me get rid of this disease? If I fix my Karma then will the suffering due to the disease will disappear ? If yes, how can I repent and to whom ?</p>
 471: <p>Let me add on to rob_mtl's good answer.</p>

<p>Firstly, diabetes type 2 is a disease that seems to be reversible and curable by changing one's diet to have less carbohydrates and to be replaced with more fats and proteins. Please see <a href="https://youtu.be/da1vvigy5tQ" rel="nofollow noreferrer">this YouTube TED talk</a>. Interestingly, the Buddha gave similar advice to King Pasenadi of Kosala 2500 years ago, in the <a href="https://www.accesstoinsight.org/tipitaka/sn/sn03/sn03.013.olen.html" rel="nofollow noreferrer">Donapaka Sutta</a>, at least with regard to reducing carbohydrate intake. Sometimes, Buddhist teachings can be very down-to-earth and practical.</p>

<p>A similar question to your's, was asked by householder Nakulapita to the Buddha in the <a href="https://www.accesstoinsight.org/tipitaka/sn/sn22/sn22.001.than.html" rel="nofollow noreferrer">Nakulapita Sutta</a>:</p>

<blockquote>
  <p>I have heard that on one occasion the Blessed One was living among the
  Bhaggas at Crocodile Haunt in the Bhesakala Grove at the Deer Park.
  Then the householder Nakulapita went to the Blessed One and on
  arrival, having bowed down to him, sat to one side. As he was sitting
  there he said to the Blessed One, "Lord, I am a feeble old man, aged,
  advanced in years, having come to the last stage of life. I am
  afflicted in body &amp; ailing with every moment. And it is only rarely
  that I get to see the Blessed One &amp; the monks who nourish the heart.
  May the Blessed One teach me, may the Blessed One instruct me, for my
  long-term benefit &amp; happiness."</p>
  
  <p>"So it is, householder. So it is. The body is afflicted, weak, &amp;
  encumbered. For who, looking after this body, would claim even a
  moment of true health, except through sheer foolishness? So you should
  train yourself: 'Even though I may be afflicted in body, my mind will
  be unafflicted.' That is how you should train yourself."</p>
</blockquote>

<p>Later, householder Nakulapita got more detailed advice from Ven. Sariputta the Arahant, elaborating the Buddha's advice:</p>

<blockquote>
  <p>Ven. Sariputta said: "Now, how is one afflicted in body &amp; afflicted in
  mind?</p>
  
  <p>"There is the case where an uninstructed, run-of-the-mill person — who
  has no regard for noble ones, is not well-versed or disciplined in
  their Dhamma; who has no regard for men of integrity, is not
  well-versed or disciplined in their Dhamma — assumes form (the body)
  to be the self, or the self as possessing form, or form as in the
  self, or the self as in form. He is seized with the idea that 'I am
  form' or 'Form is mine.' As he is seized with these ideas, his form
  changes &amp; alters, and he falls into sorrow, lamentation, pain,
  distress, &amp; despair over its change &amp; alteration.</p>
  
  <p>"He assumes feeling to be the self, or the self as possessing feeling,
  or feeling as in the self, or the self as in feeling. He is seized
  with the idea that 'I am feeling' or 'Feeling is mine.' As he is
  seized with these ideas, his feeling changes &amp; alters, and he falls
  into sorrow, lamentation, pain, distress, &amp; despair over its change &amp;
  alteration.</p>
  
  <p>"He assumes perception to be the self, or the self as possessing
  perception, or perception as in the self, or the self as in
  perception. He is seized with the idea that 'I am perception' or
  'Perception is mine.' As he is seized with these ideas, his perception
  changes &amp; alters, and he falls into sorrow, lamentation, pain,
  distress, &amp; despair over its change &amp; alteration.</p>
  
  <p>"He assumes (mental) fabrications to be the self, or the self as
  possessing fabrications, or fabrications as in the self, or the self
  as in fabrications. He is seized with the idea that 'I am
  fabrications' or 'Fabrications are mine.' As he is seized with these
  ideas, his fabrications change &amp; alter, and he falls into sorrow,
  lamentation, pain, distress, &amp; despair over their change &amp; alteration.</p>
  
  <p>"He assumes consciousness to be the self, or the self as possessing
  consciousness, or consciousness as in the self, or the self as in
  consciousness. He is seized with the idea that 'I am consciousness' or
  'Consciousness is mine.' As he is seized with these ideas, his
  consciousness changes &amp; alters, and he falls into sorrow, lamentation,
  pain, distress, &amp; despair over its change &amp; alteration.</p>
  
  <p>"This, householder, is how one is afflicted in body and afflicted in
  mind.</p>
  
  <p>"And how is one afflicted in body but unafflicted in mind? There is
  the case where a well-instructed disciple of the noble ones — who has
  regard for noble ones, is well-versed &amp; disciplined in their Dhamma;
  who has regard for men of integrity, is well-versed &amp; disciplined in
  their Dhamma — does not assume form to be the self, or the self as
  possessing form, or form as in the self, or the self as in form. He is
  not seized with the idea that 'I am form' or 'Form is mine.' As he is
  not seized with these ideas, his form changes &amp; alters, but he does
  not fall into sorrow, lamentation, pain, distress, or despair over its
  change &amp; alteration.</p>
  
  <p>"He does not assume feeling to be the self...</p>
  
  <p>"He does not assume perception to be the self...</p>
  
  <p>"He does not assume fabrications to be the self...</p>
  
  <p>"He does not assume consciousness to be the self, or the self as
  possessing consciousness, or consciousness as in the self, or the self
  as in consciousness. He is not seized with the idea that 'I am
  consciousness' or 'Consciousness is mine.' As he is not seized with
  these ideas, his consciousness changes &amp; alters, but he does not fall
  into sorrow, lamentation, pain, distress, or despair over its change &amp;
  alteration.</p>
  
  <p>"This, householder, is how one is afflicted in body but unafflicted in
  mind."</p>
</blockquote>

<p>Another interesting parable is that of the salt crystal. From the <a href="https://www.accesstoinsight.org/tipitaka/an/an03/an03.099.than.html" rel="nofollow noreferrer">Lonaphala Sutta</a>:</p>

<blockquote>
  <p>"Suppose that a man were to drop a salt crystal into a small amount of
  water in a cup. What do you think? Would the water in the cup become
  salty because of the salt crystal, and unfit to drink?"</p>
  
  <p>"Yes, lord. Why is that? There being only a small amount of water in
  the cup, it would become salty because of the salt crystal, and unfit
  to drink."</p>
  
  <p>"Now suppose that a man were to drop a salt crystal into the River
  Ganges. What do you think? Would the water in the River Ganges become
  salty because of the salt crystal, and unfit to drink?"</p>
  
  <p>"No, lord. Why is that? There being a great mass of water in the River
  Ganges, it would not become salty because of the salt crystal or unfit
  to drink."</p>
  
  <p>"In the same way, there is the case where a trifling evil deed done by
  one individual [the first] takes him to hell; and there is the case
  where the very same sort of trifling deed done by the other individual
  is experienced in the here &amp; now, and for the most part barely appears
  for a moment.</p>
  
  <p>'Now, a trifling evil act done by what sort of individual takes him to
  hell? There is the case where a certain individual is undeveloped in
  the body, undeveloped in virtue, undeveloped in mind [i.e.,
  painful feelings can invade the mind and stay there], undeveloped in
  discernment: restricted, small-hearted, dwelling with suffering.   A
  trifling evil act done by this sort of individual takes him to hell.</p>
  
  <p>'Now, a trifling evil act done by what sort of individual is
  experienced in the here &amp; now, and for the most part barely appears
  for a moment? There is the case where a certain individual is
  developed in the body, developed in virtue, developed in mind
  [i.e., painful feelings cannot invade the mind and stay there],
  developed in discernment: unrestricted, large-hearted, dwelling with
  the immeasurable. A trifling evil act done by this sort of individual
  is experienced in the here &amp; now, and for the most part barely appears
  for a moment.</p>
</blockquote>

<p>For a detailed discussion, please read "<a href="https://www.accesstoinsight.org/lib/authors/thanissaro/wings/part1.html#part1-b" rel="nofollow noreferrer">Kamma and the Ending of Kamma</a>", by Thanissaro Bhikkhu.</p>
 10967: <p>I thought to answer and hope you will find some useful trough my answer. I also have same conditions similar to yours. I would mention some characteristics about you and you can respond if I am wrong. you are thinking so fast and continuously about metaphysics like your life after death and so on....you possess some IQ more than average person. So my friend above will lead you more stressful conditions as thinking need more and more energy. I am not aware about your family conditions but be little relaxed,gentle,save some energy and maintain harmony with nature. Your intensive curiosity will make you sick. My suggestion to you is maintain your health well and leave the stress and avoid over-thinking. Don't cross your capacity without practice. Get help from others. If you have opportunity to practice "Zen" might help you. To your question "can Buddhism help to overcome physical pain?" Yes master the fundamentals of Buddhism and stick to basics. reach the path step by step. you can't skip the steps mean you waste energy and you will lack of it. Keep away thinking of your past karma aside.you can't do anything about it. Focus on present and control over thinking,get proper medicine, get gentle approach to life, stay healthy. Never forget "Health is the great noble gain in life (Arogyama parama laba) as Budda mentioned. This is the most practical solution for our lives. hope this will help you .Thanks and Metta!</p>
 4900: <p>I don't know your situation and haven't suffered anything like it, so any advice I have may mean nothing to you, but I will say these things:</p>

<ol>
<li><p>Karma is the fruit of past action. Don't concern yourself with what's past, and focus on the actions you do in the present. The Buddha said that speculating about the workings of karma is a waste of time, because it is too complex, and (at best) only fully-enlightened beings can see the full chain of causes and effects that led us to where we are now, or where we will go in the future. Kindness and mindfulness in the present moment are our tools to create good karma. Taking care of your health is a part of kindness and mindfulness, because it is important to be kind and forgiving to yourself. If you condemn or harm yourself, you are condemning and harming a future being, so be kind to yourself.</p></li>
<li><p>Practicing the Dharma and ending suffering are long-term projects. You may not be able to cure the disease. But every moment of kindness and mindfulness erases a moment of future suffering. Repent to yourself first. If, as you do this, you're moved to repent or ask forgiveness from someone else, then do that, but don't put more pressure on yourself than the disease is already putting on you. Be kind to yourself.</p></li>
<li><p>Look at the body in a moment-by-moment way and watch the way energy and pain and sensation change in every single millisecond. Watch how feelings that you think last for minutes, days, or hours are actually fluctuating in every moment. Sometimes there are eruptions of pleasant in the middle of a painful feeling. Different parts of the body are feeling different sensations and energies at different moments. Karma doesn't just act on your life, but also on every single moment within your life- the truth is, you die and are reborn many times a second. Observe the bodily sensations as much as you can.</p></li>
<li><p>You will be low on energy, and so practice will be difficult. Forgive yourself for not being a great practitioner, and only do the best you are able to. Look into the mind and see if you can find that little part of your mind that's always fully alert, always watching itself, even when you feel that you're tired and your attention is weak. Use that part of your mind to watch the rest of your body and mind and know that none of it is "you" or "yours".</p></li>
<li><p>Disease and physical health are partly the result of karma, but also partly the result of the nature of being human in a world made of matter. To be born human is to be born with a body subject to disease and death. So don't blame yourself for what's part of your nature as a human being. To be born human also means being born to hear the Dharma and to be free to act kindly and mindfully in ways that will improve your future. The fact that your karma led to a human birth means that your past included more positive karmic influences than negative ones. So be kind to yourself.</p></li>
</ol>

<p>May you be well.</p>
