Have you tried getting an arm massage?
Sometimes this helps me because the pain from knotted arm muscles gets displaced into my fingers. I was prescribed the same medicine two years ago and just like yours, they're still sitting there.
The doctors are now convinced that I'm on deaths door due to an insane amount of pressure on my brain and since I'm not eligible for the treatment, they want me to start taking even dodgier medicine, so I've been trying every natural remedy I can find, but I'm really concerned that I may be running out of time.