Several Months Ago I Started With Muscle Weakness In Both

Several months ago I started with muscle weakness in both legs. No problem at night, but difficult to get up and going in the morning. 800 mg ibuprofen gets me going after awhile and allows me to function pretty much normal except for the occasional sharp muscle pain. Am diabetic (on Metformin) with A1C under 7 and take Lipitor. Stopped the Lipitor 6 weeks ago to see if that was the cause. There has been not significant change in the muscle weakness, but even further pain in my middle back. Dr checked for back caused pain but there doesn't seem to be a connection.

The question.....what tests should I ask my DR to consider? Lyme disease? Others? He suggested physical therapy, however I am still active with golf and walking and not sure what the therapy will accomplish. Like to get at the cause.