Go to a rheumetologist to get a correct diagnosis. It is a rarity for a man to get fibromyalgia. I have had it since my early 20's and wasn't properly diagnoised until 8 years ago. Darvacet is not the drug for this. I take Celebrex and Ultram. But a Calcium/Magnisium/zinc over the counter vitamin. Also take centrum. stretching is good, not hard exercise. Swimming is good and exercising in the pool. Get 8 hrs of sleep. But before you settle with this diagnosis. Check with another docter. You need to stay active, but not to strenous. I never remember any rashes. So I am sketical that your son has fibromyalgia. Good Luck.