Interesting that your diagnosis included
2) Rotator cuff tendinopathy
which is a chronic condition, probably something that has gradually been creeping up on your for yrs. The injury and subsequent MRI should be assessed for what is 'Fresh' and what is likely to have been there already. It does should though that your AC joint might need some tweaking and possible the next to get some more long term resolution of symptoms. A partial tear though with associated tendinopathy is not something I would have injected at all. In my opinion that is likely to result in further degradation to the tissue and less likely to assist tissue healing.

Rotator cuff injuries take a long time to heal, especially supraspinatus ones. This could take 12-18 months for full pain free, non-restricted range to return. Forcing it or heaving working out when that is not the case is something I would avoid. As they say in the UK, 'Keep Clam and Carry On'! :-)