About 8 months ago I was doing heavy dumbell chest fly's and someone bumped into the bench I was on and I lost my balance alittle and tried to over compensate and felt like I pulled something in my left shoulder/delt. After a few days it felt better and thought it was ok. When I went back to my chest day I started off with flat bench and the first rep I felt alittle bit of pain, second even more, and bye the 3rd it was a very sharp intense pain. I was really upset and ended up taking 2 weeks of. When I came back pretty much the same thing but I tried to work through it and it jsut got worse and worse. I ended up taking 3 months off it got so bad. Ok so now I am 3.5 months later, shoulder feels fine, havent felt any pain for a few weeks so I go back to the gym. I go to flat bench, and same exact feeling as before. 1st rep felt it alil in my side delt/shoulder, 2nd more, and 3rd it was killing me. The weird part is the symptoms and how it feels. In the beggining and first few reps it just feels like my left shoulder is working harder, I get more of that lactic acid build up feeling and just feel liek theres more weight on that side. As I go further into the workout and add weight is slowly progrsses to a sharp pain and gets more and more intense. Because I took off 3 months I am using light weight, and my other side feels fine. but on my left side it feels like my shoulder is doing all the work and getting killed. after my workout My left side feels like I worked it out REALLY hard, have that muscle burn, and my left shoulder is weak and feels liek its hanging, and my other side is fine. Fast forward 20 minutes after my workout 90% of the pain is gone. I can still feel like something is wrong, but not painful just "weird" and barely noticeable. Only time i notice it during the week is if I am on the couch laying on it weird it jsut feels liek its being worked hard, and being strained. Im at a loss because I took such a long time off, and figured it would heal. Add on that 20 minutes after the workout it pretty much goes away I have no idea whats going on. I am going to see a doctor next week, jsut wondering if anyone knows what this may be. I should note I do sometimes feel it on Bicep exercises, which makes sense for some shoulder injurys. I havent lost any range of motion or anything, just the symptons I have posted. PLEASE HELP!!!! I