Hello, so I had chest pain after exercising. It started feeling like heavy pressure kind of like a sore feeling, right in the middle of my chest. It was hurting for about a week exactly, like it hurt when I would run, walk (but the pain was very very minimal when walking), when I would lay down (only hurt when laying down for about 4 secs, then would go away) and basically any physical activity. However today, it does not hurt when I run, walk...it still hurts but very veryyyy little when I lay down and jump up and down (pain is a 3 from a scale of 1-10) I do not experience shortness of breath or anything else, so what could it have been? Again the pain felt like pressure...Should I still be worried? Could it have been a muscle strain? I am 20, female, 5-02 and 155lbs. Thanks!!