I blew my shoulder out almost 25 years ago now doing dual slalom on Seymour one summer. 3rd degree separation. It took about 2 months for me to get mobility back and I was rock climbing again in 3. For years after that the shoulder bothered me. Not so much in day to day or mountain biking but thing like I couldn't carry a bundle of slalom gates down the ski hill on that shoulder and I would always get a kink under my right shoulder blade for years.
Finally a trainer I was seeing started me exercising the shoulder more specifically, flys, shoulder press, etc. and I stretched a lot more. Much better. To this day though I still can't sleep on my side comfortably on that side. Not good for my wife when I sleep on my back and snore like a down shifting semi! LOL.