I just completed therapy for my shoulder last Friday. They told me to use the rubber bands for continued workouts, at least for a time. I asked about going to the gym and was told that would be fine for lower body work, but I should work my shoulders extensively with the rubber bands before going to weights. I previously had surgery on my other shoulder, and it went well. Right now I am shooting my 40# bow, but by the fall, I hope to again be able to handle my 53# hunting bow
comfortably.
Overall, the bands provide more of a stretch than a power building workout. It seems that stretching has worked for you as well. Continue the stretching and a slow and continual strength program. Don't rush it. You did not mention a medical check up or a physical therapist. I think that is important so that you can map out the most beneficial exercise regimen. Good luck with it, and pay attention to Mike Bolin and the others.