So, I had problems ,still do sometimes. What I found out- I was diagnosed with IBS when I was a teenager, little over 50 yrs ago....lol. Abdominal pain and bleeding from the irritation. Took metamucil twice a day. Bothered me off and on for years. Bloating, back pain, right or left flank pain, but it would go away. I would eat more easily digested stuff, drink fluids, that kind of thing. When I got older and hormones changed, I had another bad bout of it. So I had a colonoscopy when I was 49, found some polyps, some gastritis, took some Nexium. It bothered me now and again after that but it went away after a couple days. Then as I got in my 50s and completely quit smoking I had a few horrible bouts of that pain and diarrhea. It was mostly right sided, some back pain, and it was a biting flank pain when I took medication to stop the diarrhea. Another colonoscopy, but this time a different doctor took biopsies of my gut and came back with lymphocytic colitis. I took budesonide for a few years and got off that when I started taking pre and pro biotics twice a day, bkfst and supper. I still get diarrhea once in awhile if I eat too much at once, or really greasy foods, or something hard to digest. Also take Metamucil in the evening , only 1/2 a spoon these days. I know what that pain is like and I feel for you. Gastroenterologist can help you and try to figure out what you eat that does this. IBS, IBD- because lymphocytic colitis is classed that way, and SIBO. My husband gets irritated when we shop because I read labels like I'm getting paid. Good luck to you; hopefully you get some answers.