I get that too, but i was told it's due to my anxiety, but man.. sometimes i'll get a BAD pain and it feels like my heart flutters and i lose my breath for a second. I'm wondering if it's really my heart, or maybe my chest muscle having a spasm or something else. If it was something bad though i think it would happen all the time, and would also occur during anything physical. it's weird how i could just be sitting relaxing and all of a sudden feel that sharp pain, and like you in comes and goes! which makes me think it's anxiety related, sometimes i wont get it for weeks! then other times i'll get it every few days.