What Is The Treatment For Severe Pain In The Legs And Arms Of A Child?

Hi, may I answer your health queries right now ? Please type your query here... My 3 year old son wakes up in the night with extreme pain in the legs or arms. I noticed that this happens only when he has has rice or potatos to eat anytime during the day. I stopped both these for several days and no pain. I introduced rice (basmati) and he again woke up with pain. I tried this several times in last few months and result is the same. However, items prepared with ground rice or rice flakes (rice pasta etc) have never caused problems. It s not growing up pains for sure. He also has milk & wheat allergy. It would help if he could have some whole grain rice dishes. Any help?