I was diagnosed with a numb sensation in my right thigh. It did not bother me then, but I thought I should get it checked. That developed into pain, particularly on trying to get out of bed, when I was put on simvastatin. The pains went away for a time when I stopped taking it. Dr tried me with niacin for cholesterol, & within 3 weeks the pain was returning, & my fasting BS went up from about 6.7 to 7.2.
I've been using metformin for 5-6 years, but that doesn't seem to cause any problems. 2 years ago the background muscle pains became intense, making it very painful to get out of bed. At that time I joined this forum. Reducing the carbs has cleared the pain & restored my active life.
It seems to me that the muscle sensation that sent me to the Dr for diagnosis is an early warning system for the adverse effect of any drug or food-stuff, & it intensifies if there is an adverse reaction.