Sour upper stomach after eating fresh sliced pineapple

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I ate small bowl of fresh pineapple I cut and sliced. 1 1/2 hours later flood of diarrhea and sour upper mid stomach. Diarrhea 1 1/2 days but sour stomach for 1 month. No vomiting or pain just sour stomach and tired, prob from light diet. Dr. Said irritated stomach g  as well me light diet to follow, covid test and it was negative. I lost 4 lbs in month and now stomach is just not right but at least I can eat more comfortably now. I think I need colonoscopy or something else?