I have two frozen shoulders, the left one was first ( about 13 years ago) and I had a cortisone injection in the shoulder, which was very painful and didn't really do anything, physio at the hospital was the best, and really helped that shoulder, but a few years ago the right went the same way. My motto is, use it or lose it, I do a little bit of a stretch exercise every morning and I continually use my arms as much as possible, so for me, being flexible does help.