If insulin isn't keeping your Bg down enough, you could always try very reduced carbs. keep testing and reduce your insulin if necessary.
If you are in pain, it's definitely worth a go.
Another idea. Do you have a good sports centre nearby, where ther's an exercise therapist? These folks often work alongside physios and can be extremely helpful. At my local authority owned Sports Centre, there are classes for people with health iswsues and an excellent sports therapist, who I know works on the Stroke Unit and with MS patients as well as others.
I know it sounds as if a person with muscle problems and chronic pain can't exercise, but a good exercise therapist can tailor the activities.
I find nothin taakes the aches out of my muscles like a bit of exercise( but then mine are basically OK