Hello, In my opinion your child is suffering from intestinal parasites to cause pain in lower limbs along with raised uric acid.
He should tk plenty of water to hydrate his body elimnating uric acid through urine.
be easily digestible, non irritant on time.
Give him homoeopathic medicine:@ Acid benz
30-6 pills, thrice. @ Cina
30-6 pills, thrice.