5yr old son complaining of upper thigh pain right side only. Not constant, but has been for 2mths or more. Says he can t run a long time. Only complains on rare times. Any ideas? It is not at night - the pain seems to be at random when he mentions it. Sometimes it hurts to touch or walk.....has not had an injury that he (or I) can think of. He is a very active boy, and enjoys falling :) Wondering if I should be taking him in to check for groin or muscle injury? Thanks