Nagging Shoulder Problem?!

So i have been dealing with a shoulder injury for awhile now. I separated it around October 2009 in a soccer game. Well now move to now. It is stiff 24/7. And half of the time i have this consent dull pain with a few short times a sharp pain. There have been a few times where there have been big pops. For instance a month ago i rolled over on my bed and there was this big pop in my shoulder with a few secs of pain than went away. Than last week i was waiting for my next class to start and when i moved my shoulder it had another big pop. If you put your hand on my shoulder and i rotate it clock-wise or counter clock-wise you can feel and hear it popping a few times either way i row it. Also if i take off my shirt you can see that the injured shoulder is lower than the other shoulder. I tried doing military presses and such there were a few times that there were small pops. It is now stiff and there is a dull pain. It sounds like it has to do something with the rotator cuff but thats my guess. What do you think is wrong and what do you think i should do