HI! I Am Having A Hardening In My Abdominal Wall.

HI! I am having a hardening in my abdominal wall. I have been to the ER on many occasion and have had Xrays and CAT scans in, which they have told me that there is nothing wrong. My stomach is hard off and on also I have celiace disease. I have been staying away from foods tat have gluten however I am continuing to experiencing the hardening in my stomach. Do you have any idea od what it could be. I am afraid that I may have a tumor of some sort.