Hi Richard,
Some observations I've made over the years:
Diabetes and some forms of Arthritis are both caused by auto immune problems. They don't know how to fix those yet without serious side effects.
Glycated tendons, caused by running high sugars over a long period of time causes symptoms that resemble arthritis. It can be reversed or lessened by being in control.
Running high sugars can cause nearly any pain I encounter to be more severe. Some kind of nerve thing? Who knows, it's one of those things they don't know for sure YET.
If they don't know the exact mechanism of joint or muscle pain , they call it fibromyalgia. There are a myriad of suggested medications prescribed for this. As far as I am concerned, this is a non-diagnosis that means basically "You hurt."
Any medication or combination of medications that work for you for any of the above conditions are the right ones for you.
Not much help, I know. My main point is that sometimes there are no known and sure answers. Even highly educated guesses provided by doctors are just that--highly educated guesses.
Who is it on this board that says his life is an ongoing science experiment? Mine has been too. It's the nature of Diabetes and a smart diabetic keeps learning and trying.
Some day they'll know it all. Just not yet. Think of yourself as a pioneer.

Mich