I have been having problems with under-active thyroid for 30 years (since 1st child was born). Now for some unknown reason I can not take my thyroid med. It causes chest pain and my doctors do not seem to know why. I've been to an endocronologist and she had no idea either! We have tried synthetic and natural hormone! I really need to find out if anyone else has had this happen to them. I have not been able to take my pills since 2000 and I am getting so tired that I can hardly walk. My legs feel like lead weights and I am in bed most of the time - not to mention the weight gain.