HI ! What is the dietary habit of your son. He must be going to school. Does he take junk food frequently from outside. You have to give proper attention to it and counsel him if he does. To me it seems like he has got simply collitis due to his possible irregular food habits. Get a routine stool test
done for ova and cyst.
Please get him clinically examined by a general surgeon
specially when he is getting the symptoms like cramps. Is his belly distended at that time ! After that does he passes a lot of air after which he gets relief. If this is so, he has to be examined to exclude a sub acute kind of intestinal obstruction
which could be due to minor adhesions of intestines with the appendix scar
. The surgeon may to for an X-ray abdomen in upright posture, and an ultrasound
abdomen to investigate and if these do not help, may be a CECT abdomen.
I wish your son an early recovery.