shoulder pain?

[chels]

For a few years now I have had pain between my neck and shoulder, sometimes stretching down to the top-middle of my arm. It's usually on my left side (I honestly can't remember if it has ever been on my right). It's been getting increasingly bad so I think a doctor's visit is in the near-future. I just wanted to see if I could get an answer here first while I am thinking about it. When the pain comes, I have to admit that it is pretty bad. Sometimes it is hard to breathe. I used to only get it when I would run, but now it comes whenever. I had reason to believe it was a pinched nerve but I don't want to self diagnose myself. I have had problems with my right shoulder due to a sledding accident last winter, but I really don't think it is related because the other pain was here before that. Any help would be much appreciated!
Oh yeah! It feels a little better when I apply pressure or hold my shoulder close to my body.