I'm a 24 year old male in fairly good physical health, though I do smoke. For the past year or so, I've been experiencing sharp chest pain to the right of my sternum. I first noticed it one night while I was sitting on the couch watching tv. When I run for a long period of time the pain is intense, it gets even more difficult to breathe and the pain extends up into my right shoulder. I've seen two doctors about it and naturally I wasn't in pain either time, and the first one said he couldn't see anything wrong and the second said he "thinks" he might have heard a slight murmur but didn't conduct any further examinations. In both cases they said I was fine and not to worry about it and to quit smoking. Question: What is the most likely cause of the pain (and if you say smoking I'm gonna scream. I'll concede that smoking is a contributor, but it's not what's causing the physical pain--although I am trying to quit). I'm hoping that someone will recognize the sysmptoms and be able to give me a few names of conditions that I can take to my doctor and say "Test me for these, please."