What Causes Pain In The Chest?

I've been having shoulder pain in my right shoulder for a few years now. It has been bad enough that I quit sleeping on my right side, and I have taken to stomach sleeping (which I never used to do). In the last month, I started getting pain in my chest. It happens when I move (on occasion), and it feels like I have bones moving around in the middle of my chest. I'm 35, 5'8, 155 lbs.