Seriously, I have a chronic shoulder injury that is probably mild compared to what some of you have experienced. Even a mild injury can stop your progress dead however.

I have gotten stronger on every lift except bench and incline in the last two months. My bench and incline have dropped because of the shoulder. Really depressing....

I recently stopped all lifts for 4 weeks that even remotely hurt my shoulder (Bench, Incline, Military...even heavy shrugs are out)

I also got a shoulder horn. I looks kind of goofy, but man does it isolate the external rotation muscles. I can already feel a difference...and that is encouraging.

A couple of suggestions...DO NOT let a Doc shoot you up with cortisone. When I first went in the guy whipped out a big syringe and I said cool. I kind of like needles in joints. But now I wished I had not let him shoot me up. My shoulder hurts in a whole different way now, and feels weaker. That is one of the reasons I took off 4 weeks.

Also consider limiting range of motion on presses to where you shoulder naturally wants to stop. With a bar, this means stop the bar 3-4 inches above chest. You can still use normal for once in a while (maxing out, etc) but don't do it every time. Your shoulder was not meant to take that stress in a position which has the joint capsule pulled open.