Hi Mairi,
I'm sorry you're having trouble with your shoulder. Mobility devices can certainly cause a lot of aggravation. Have any less invasive treatment methods such as an ultrasound guided cortisone injection been tried for that angry bursa? These can be helpful in getting the bursa to calm down. Sometimes they can remove fluid by needle from the bursa as well. Something like this would be less risky than surgery.
I know it can be scary increasing the level of help you get from mobility devices. However, if the temporary use of an electric wheelchair would allow you to heal with rest and PT that could be a very thing.
If you do need to go ahead there are things your anesthesiologist can do to reduce the risks. Biobased posted an article not too long on surgery and CRPS. It is in the "I got bad news today" thread a few rows down.
Good luck and hugs. I hope you recover soon!