Nagging Shoulder Injury?!

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. 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