Hi,
Welcome to the ehealthforum. I am glad to help you out. I can understand the pain and agony you are going through. Any pain in the chest should not be taken lightly. However, if you have been examined by the doctors and have assured you that the pain in the chest has got nothing to do with the heart, then you should not be worried. However, one of the tests which can rule out the possibility of the heart disease is the TMT or the stress EKG test.
You can request your treating physician to go ahead with this test. If it is negative, then the chest pain is possibly due to anxiety only. The nicotine withdrawal can also produce or exaggerate these symptoms. You can always discuss this with your physician regarding the option of using the nicotine gums or drugs like chantix (varenicline) which can facilitate in giving up smoking without producing withdrawal effects.
It is very difficult to precisely confirm a diagnosis without examination and investigations
and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.