A 46 year old man with incidentally elevated CPK in the psych. service

I came across the following issue in my psychiatry rounds. This is a 46 year old African American male patient who has had persistently elevated CPK's and at one
point even the MB fraction was slightly elevated. The highest CPK was up to
1500. Now it is lingering in the 400's. MB is normal. Trop I has been normal. He
is not clear about muscle aches, but he does get up feeling stiff. He is newly
diabetic, and has not been on statins that obviously could cause myositis.
What should be done? I already talked to a fellow neurologist that
told me this could be benign. But what does it mean?