I was in an auto accident about 3 years ago and my left shoulder was injury. I did therapy, medication, and the whole nine. When I got back into lifting, everything was fine. For about the last year or so, my left shoulder has been bothering me. No matter how much I drop the weight, my left should fatigues way faster than my right. That happens when I do dumbbell exercises mostly. I'm concerned it will feel like this forever. What should I do? I definately don't want to stop lifting just because of a naggin' injury.