Shoulder frustration

Any one who has read my previous posts knows that I've been having some shoulder problems. I've been to the doctor several times and everything has been going good. I've been doing rotator cuff strenghting exercises for about a month, every day, and the doc said that my shoulder strength was doing very well. But for about the last week or so, it has been aching down in the AC joint where my bones are rubbing and clicking together (one is sliding under the other), causing the pain. I thought that since my shoulder was stronger that it should be holding my bones in place, but it started aching like it hasn't improved at all. Then the other day at work, I was carrying a bucket of ice and the muscle on top of your arm..not sure what's it's called, not the bicep but the one that is to the outside... felt pulled and it kept felling like it was pulling my shoulder joint down; it kinda felt like it was pulling it out of place downward, and the doctor said that my shoulder only popped out slightly to the front now so I've been doing back exercises. Now today my whole shoulder is sore. Has anyone else with shoulder problems experienced something like this before? Should I go back into the doctor or just take ibuprofen (sp?) regularly and keep doing my exercises. Thanx! ~Kyra