Skip waiting for NHS physio and go private. I went to see a sports medicine GP (private) for my diagnosis, well worth the money.
I hurt my infraspinatus and supraspinatus in May in a crash on the road bike. Thankfully road riding doesn’t hurt my shoulder as long as I don’t stand up to climb or sprint. Still have a lot of pain when sleeping if I lie on that arm, putting on jackets and certain rotations/movements. Lost a lot of overall shoulder strength which has affected my scapula too. What seems to have made the biggest difference in terms of pain is doing my physio exercises every day (funny that). I had an 8 day tour in the Alps booked less than 2 weeks after crashing and was so desperate to make progress that I resorted to adding turmeric to everything (cous cous, tea (grim!) to help with inflammation (on top of anti inflams).
Turbo should be ok if you *have* to exercise.