yep i do cuz i used to get them all the time. whats happening to ur legs is this: the muscles that line the back of ur legs are getting dragged off to the side as you walk. over time the muscle tone becomes to high and starts to sting.
sit on a chair, twist your foot out and raise your leg slowly. repeat on your other leg.
ask a physical therapist about it to make sure we're talking about the same thing. most doctor's tend to ignore a cp patients complains as "cerebral palsy is not a painful condition."