I've been on Metformin for 2 months following a steroid shot I had in my knee. I am a steroid induced diabetic and was supposed to be on the metformin for another month, for a total of 3 months due to the fact that steroids make my sugar go Sky High. The first month of Metformin gave me severe diarrhea and stomach cramping. This subsided after the first 4 weeks but then unusual muscle pain started. It started at the base of my bottom are my legs attached to my body. Then it spread to my hips and then down the front of my legs. It starts at night when I'm sleeping but gets better once I am up during the day, but not always. I found your forum and see that this has happened to other people as well as some kind of side effect from the metformin? I talked to my doctor and I'm going off and Metformin for a few days to see if this pain subsides. But doesn't seem to be anything I can take for the pain either so I'm hoping that going off of it will make it stop. I'm pretty good controlling my diabetes with my diet so my doctor thinks I could stay off of the metformin unless I need another steroid shot.