what is wrong with my stomach?!

march last year, i had a bad stomach bug/virus. after this, i kept getting regular diarrhea. i went to the doctor almost every month, i had stool tests and blood tests. they found no bacteria and nothing in my blood test. still, up until this day, i still get regular diarrhea. i also get quite alot of acid and back pain.

RECENTLY, for about a month, ive been getting a sharp, twinging, dull, pain under my left rib im also getting my diarrhea more frequently too. the pain is super annoying and so is the diarrhea! what could this be? could it be something like IBS or something more serious?