I have been having mild pain in my left chest since 3-4 days now. I keep thinking it is gas pain as previously I did have this kind of pains. There was slight burning sensation in my middle chest and sometimes I feel the pain in right chest also. I tried drinking lot of water and I had to belch to let out the gas. But when I climb stairs I feel the pain can be felt. Even at rest, the pain comes and goes with no other synmtoms. Is it just gas or anything more serious like heart attack?