Hello. I Have Been Tested For Gluten Intolerant Along With

Hello. i have been tested for gluten intolerant along with many other things. i take a strong probiotic from my dr and i still struggle bad with digesting food. it's like it sits real high for days. i only poop about every 3 to 4 days. as soon as i take a bite or two, not a whole meal, i instantly get this bulge knot thing at the top of my tummy and it hurts and very uncomfortable.
could there be another cause or test i should ask for...