Obviously no two injuries are identical but this sounds a lot like the issues I was having with my shoulder starting a couple years ago. They took x-rays and an MRI and decided that while, yes, there was some general arthritis going on, nothing was torn that could be "fixed" and long term physical therapy was the only option. I was diligent with my exercises for a while but things never really got 100% and I got discouraged. A few months ago though I started getting regular massages and the guy recommended a few specific things for me to do to relieve all the tightness in my neck and back and since they are easy to do I do them and they seem to also be improving things in my shoulder.
I hope your issues can be addressed and you get some relief soon.
I'm going to get an injection and then PT.
I like the idea of massages...
PTs can vary in capabilities but I was sent to one with my severe shoulder injury a couple years ago. He did a full range of diagnostic range of motion, strength assessments and set me up with several weeks of exercises of increasing loads as my shoulder recovered. He was good, but I've had others not so. They vary as I said. Good luck with it.