Welcome to the family, Diddle!
I feel your pain, truly! I have had bursitis & tendonitis in both shoulders. I had the tendonitis after taking an antibiotic - Levaquin! This seems to be a common reaction to the medicine, unfortunately.
I wasn't able to use my arms, so my pcp sent me to an ortho, who in turn sent me to PT. I got some ROM back, but not enough to 'write home about'. :(
I would suggest you ask your dr about the PT. They generally want you to use those parts, not keep them immobile.
At PT, they used a heating pad, did exercises for the shoulders, had a massage (yes!), then they iced my shoulder (not my favorite part). W/o all those steps, I don't think I would have gotten back what I did get back.
I wish you the best.
God bless. Alice.