<s>[INST] I am 16 years old, I am feeling lightheaded, sometimes I get these slight chest pains & fast heart rate, I have had 2 ekg s, 2 chest x-rays & 2 blood samples. They all came back fine, what could be causing this? I m taking medication for GERD (just in case it is that) & cutting out caffeine. What could be causing my lightheaded feeling, slight chest pain, soreness or pressure & varied heart rate? [/INST] Thanks for your question on Chat Doctor. Since your cardiac and pulmonary work up is normal, I think your symptoms are related to stress and anxiety. I just want to make sure that blood reports you are telling includes hemoglobin and thyroid reports. As we need to rule out Anemia and thyroid problems in your case. So if not done than get done CBC and S. TSH. If these are normal than it is anxiety and stress related only. Better to consult psychiatrist and get done counselling sessions. Avoid stress and anxiety.  Be relax and calm. You may need anxiolytic. </s>