Coeliac and gastritis

hi, i don"t know if anyone can help but does anyone know how you control both together? i am currently having a nasty gastritis flare up and can’t pinpoint what has caused it. how restrictive is my diet meant to be and does one spark the other off? i just need some advice. anyone???

quick update, whoops sorry not gastritis, now confirmed as costochondritis. ow, ow, but not gastric!