Pain in leg. Kindly help me in this!

My father experiences pain in different regions of the leg. He feels it to be caused by a nerve as the pain shifts places within the leg. Pain shifts to a different region of the leg in about 2-3 days time. Pain is felt majorly while walking and almost non existent in sitting and sleeping position. He has experienced this same pain 4 yrs ago which had vanished after around 2 weeks at that time. Currently he has been experiencing the same over 3 weeks now. Local physician has taken scans in the region of pain(leg) which indicates everything to be normal. I (son) want to take him to a specialist doctor. My question is as to whom should i be visiting A. Neurologist (with neuromuscular expertise ) B. Orthopaedic Or some other specialist... Kindly help me in this regard.