I am experiencing leg pain in both legs when I stand and put pressure on them like standing still. When I walk and am moving, my legs don't hurt. I feel pain down the backs of my legs especially behind my knees, my hamstrings, and calves. They also ache when I am sitting on a hard surface. Any pressure to the back of my legs make them hurt. It feels like my muscles are being pulled on. It is a dull but powerful pain. I am at a loss of what it could be. I am healthy and a personal trainer so I am quite active. It is not muscle strain. It would be so helpful if anyone could respond that might have a suggestion as to what it might be.