I ate sauerkraut (cabbage) and felt terrible pain in upper right stomach. i have coeliac disease. what can i eat?

Lots of things!: http://celiac.org/live-gluten-free/glutenfreediet/food-options/ The Celiac Disease Foundation has guidelines on what you can eat with Celiac Disease. Just cut and paste the link above into your browser. Normally cabbage is ok in celiac disease, but some people get gas pains from cruciferous vegetables, especially if you eat a lot of something you aren't used to. Try a small amount.

Sauerkraut ok: Sauerkraut typically does not contain gluten. Also, celiac symptoms are usually bloating and gas and not usually severe pain.

Acidic: Cabbage tends to cause gas and vinegar is acidic and the combination was what caused your problem especially if you happens to have reflux or gastritis. This is not from celiac disease which happens to be fad disease of this decade.