Thank you for your query.
Unfortunately you have not mentioned the age of your son. Presuming that he is around 3 years of age children do complain of such pain which is know as "growing pain". Nothing needs to be done for it as it subsides on its own. You can ask him to soak his legs in luke warm water before retiring which should give him some relief.
As your son is also complaining of pain in the arms it may require a detailed examination by a doctor for the likely possible causes. The doctor would like to do a complete neurological examination for the pain and tingling sensation
I hope I have answered your query to your satisfaction.
Wishing your son an early recovery.
Rajiv K Khandelwal