Thanks for the initial response about the 10 year old with pain in the leg. He was seen by a doctor and given pain relievers, but pain still persists.?

Pain in legs. In ten years old most of the times it is growing pains but if it is persisting and is localised in one leg and limited area then you need to have xrays to rule out any other [pathology.I am presuming the pain is in legs and not in any joints like ankle, knee or hip which will make it different.
See a vein doc. Look up a vein specialist called a phlebologist, www.Phlebology.Org who evaluates children for venous malformations. At least have a venous doppler, ultrasound by a trained vein specialist and their sonographer. Also see a pediatric orthopedic doctor for evaluation.