question: hello, I'm 21, very active, i play tennis, gym, soccer etc,not really any medical history to note, always been very healthy. recently I have been having slight chest pains now and then, nothing major, however about 3 weeks ago I was doing sit ups in the gym, i did about ten and then felt a very intense pain in my chest, around the sternum. It was so baad i could not move or push myself up to stand up and I had to wait a few minutes for it to go down before I could move. Since then It has been hurting on and off, the pain varies from the left side to the right of my chest. Any idea what this could be?