I have a muscle cramp......Charley horse really....upper thigh, in the back, killing me. Sitting is horrible, standing is a little better, no amount of stretching has stopped it. Just walked two miles, still there. Been all afternoon now. I have had it recently, once a day or so, but got rid of it each time by stretching or going to bed. I need to know what I have to do to make it go away and not come back.......any suggestions?