What Causes Frequent Pain In The Palms And Soles Of The Feet?

My 5 y.o. boy has frequent pain in the palms of his hands and soles of his feet. The pain more commonly occurs in the lower extremities and is often (but not always) bilateral. When the pain occurs there is no apparent skin/surface irritation or swelling. It has been going on for years. What are some possible causes for this. We try ice, ibuprofen, stretching, massages with biofreeze or peppermint/wintergreen oil but it does not seem to help. We just have to wait it out. The pain is severe he cries and screams and is unable to continue participating in whatever ax. he was doing at the time. His pediatrician has suggested growing pains but it happens so frequently for so many years I m not convinced. The pain comes on abruptly. His pediatrician has also suggested supportive shoes because he has a low arch - we do this already. My child is too young/unable to distinguish between stabbing/burning/tingling/cramping etc. but he does articulate that the hand and feet pain feels the same. He will state, I have foot pain in my hands . What could this be and what else should I try?