So I'm a 16 year old female and I have been having these problems. To start off i will tell you I'm 5'3 and i weigh 112 pounds, and here are my symptoms. For a few years now i have been having a pain in my chest like it tightens and it gets hard to breath/swallow (Happens even while im on the computer like now). My heart races and pounds hard, my pupils get huge (where it happend it school this week and my principal asked if i was using drugs) My neck goes red and my body feels as if it is shaking side to side and tilting. Usually when i get these feelings i pass out. I had passed out about a month and a half prior to this and my Doctor made me wear a heart moitor for two weeks and nothing has come back wrong yet. Also i have had two ECG's and it was also fine. The only thing they found was that my iron was low and I've been taking iron pills for about a year now. That would be the only pills i take other then Birthcontrol. The only other thing that happens to my body is my toes and fingers get really cold for no reason, but i cant sleep with socks on or i feel as if im sufficating at night, my doctor just said i have to cover up more and wear gloves. IF you have any opinnions as to what i should do or what it might possibly be. PLEASE reply. Thanks a bunch! :).