<s>[INST] i am a male 40 yrs old.i have been having a mild back ache on the upper back.it is at times on the left and at times on the right.i at times also have a mild ache on the chest.it comes and goes.certain days there could be no pain at all.when it is hot, there is no pain.i am having hypo thyroid and taking 50mg eltroxin. [/INST] Hypothyroid patient use to have side effects like fatigue, weakness and pain in muscles, stiffness in muscles, increase body weight due to water retention, and increased heart rate etc. Here you have explained you have mild back pain which is radiating to the chest. There could be few possible causes for this. 1. It may be because of muscle weakness and stiffness in back muscle as a side effect of hypothyroidism or mechanical back pain too.2. Chest pain could be because of increase water retention in body and increase heart rate putting more pressure on heart. Here for both above cases I suggest doing thyroid test and if it's not in control do proper treatment. Even after that if you have mild back pain I suggest getting examine your back with physio or or tho and take treatment. As well follow postural correction and spinal exercises as per physiotherapist guideline. For chest pain check if it is increasing walking up hill or while exerting yourself with breathing difficulty. If it is increasing then do ECG and treadmill test and based on result consult a cardiologist for proper examination and evaluation. As well, he will also help for treatment. I am sure you will be fine if you just follow above steps. Take care </s>