I'm a smaller guy,skinny, 23, been trying to start lifting weights for a few years now in order to stop looking like a malnourished child, but every time i do an injury in my shoulder flares up. It;s at the back of my shoulder and also inside my shoulder blade sometimes, starts off not too bad but if i keep working out it gets very bad. I got an MRI on my shoulder and the Doctor said my tendon swells up causing pain when it's put under stress. Can anyone recommend something to try fix it?