Metformin Hydrochloride and inflammations

I've been on Metformin for about the past three years. I'm now 65 and a half, and I've recently decided that this drug has caused me a lot of muscle pain, making it hard to take walks (which I force myself to do) and to sleep. I used to put this problem on my age, but since my doctor has been cutting my prescripts back, I am improving. In fact, if I miss a day or two of the meds I am much better. I've never been on Zocor or any Statins (my side effects sound a lot like those mentioned in the Zocor Forum), and refuse to go on them, and am now wondering if I should refuse to be on this stuff any longer, as well.