seperation in my ac joint

About a year ago I seperated my ac joint. I never got it looked at until about 5 months ago and started seeing a chiroprator, he did xrays and found the seperation in my ac joint. He said it was a 2nd degree, almost a 3rd. So I started having him adjust it and he would also do a few stretches. We did this for a few months then sent me off for a cortisone shot, which I recieved a month and a half ago and that was it. The pain went away, except for I couldn't do flat bench or close bench or a few flys still, so I just stayed away from them. Now the last 2 weeks it has started to come back, and I'm guessing because maybe the shot is wearing off. It doesn't hurt as bad as it use to but it's something I'm still concerned about and would like to go away. My chest workout is pretty much limited to decline and incline, those are the only 2 that don't bother it. My question is what do I do now? Any advise on what I should do? This has been very depressing and starting to feel like I'm never gonna be 100%.

Also on another side note, I'm about 6'1 with a very long arm span so I've always had problems with my shoulder. I read somewhere that switching to decline would be better for me because it shortens the range of motion and puts me in a position to hit my chest better. Any feedback on this?

Thanks bros,

TUnit