For the last couple of years (I'm 19 now), I haven't been able to run due to various symptoms that come up when I run. It started when I would get shoulder pain when running, in one of my shoulders, sometimes both. It felt like a vein at the top had too much blood going through it. Then I started getting chest pain. I'm not sure if it is my heart or my lungs, but I almost collapsed on a treadmill the last time I tried to run. When I swim, I get none of these symtoms, and I was on a relay team. I really want to be able to jog and run, but I can't deal with the pain. I worry that it is my heart. I went to the Dr. and got no diagnosis.