I have had and rehabbed from severe problems in both shoulders including something loosely similar to what you describe. Here are some thoughts.
- Avoid any movement that seems to make it worse
- Do light movements to get blood into the joint through every possible range of motion
- If you can do standing rows with very light weight without making it worse, that helped me a lot
- As always, DMSO and BPC patches if you have them. Supplement with collagen.
- Red light if you have it
- Diclofenac gel can mask the pain and may help with reducing inflammation, but you want to make sure you don't re-injure the joint when you don't feel pain. Same with Gunther's gel.
- There's no telling how long it will take to fully heal, but my experience is that shoulders (and joints in general) take much longer than muscles to heal. Mine each took almost a year but what I had was much worse than what it sounds like you have, but don't be alarmed if it lingers for a couple of months.
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