Could alternating flatulence, constipation, and diarrhea, with minor pain under the lowest left rib, be due to my redundant colon?

Probably not: This question has been studied over the last 75+ years. There is no definitive answer. Most bowel specialists believe that redundant colon is a normal variation. The alternating flatulence with constipation and diarrhea are classic symptoms of irritable bowel syndrome. After serious colonic diseases have been excluded there are several effective treatments including fiber, fluids, meds, etc.