I ate a bite of pizza two days ago dull aching pain all night 6-7 hours. ate a few slices of pizza; stomach had painful dull pain for 6 hours. now stomach cramps. i took a break from gluten/wheat. now his happens after pizza. could i be allergic now?

Pizza has: so many different ingredients possible. Does any other bread type food give you the same problem? You could be sensitive to a food preservative, spice or gluten. More investigation is needed.

YES: however could be lactose intolerance from the cheese on the pizza. I suggest holding off on breads initially and then cheeses ( elimination diet ). Requires medical/allergic evaluation.

Yes: You could. Ask your doctor if celiac panel test is appropriate for you