Is your son an active child? If yes, then these are bound to happen in him.
They do not signify any major health issue in him.
He may not be eating adequately. You need to give me food at regular intervals. Make sure he does not skip a meal. Give him plenty of fruits and vegetables.
Pain in the legs and feet may be because of physical exhaustion due to too much sport.
Give him a dose of deworming medicine like Albendazole
I strongly feel he is fine.