Hi, i am a 20 year old 5ft tall 100lb girl...i havent had any medical conditions. i am physically fit and ocasionally active..i have been having bad chest pains around my heart that go down my back. i havent eaten anything in 4 hours... i took gas x and that hasnt helped although when i stand up i get some relief...this has been happening a couple nights a week for the past month..i drink a lot of diet pop, so i am wondering if the carbonation might have something to do with it? what is wrong with me?