He started with a niggly pain under his belly-button on Monday.Then he said it had "moved upwards"and gone to both sides-around the rib area.He is a very active lad and has been finding it hard to do anything physical for the past 2 days.This morning,I thought he had improved,but when he got to school he rang me and said he was in agony.The pain sometimes is more harsh on one side more than the other-no specific side though and this morning he said it's in both again.Could this be something more than just muscle pain?