Constant lower pelvic pain/painful to pass gas and stool/nausea/fatigue/ mucus in stool. colonoscopy/egd/ct scan/ /stool test normal. any ideas?

Constipation: You mentioned that all the test are normal. Constipation can cause nausea, fatigue, pelvic heaviness, and painful to pass stool and gas due to exertion. Drink a lot of water/fluid, increase fibers in your diet, and chew your food well before swallow. Drink a glass of slightly warm water with little salt early in the morning. Exercise regularly, everyday walk is good. Try probiotics. Consult GI doc