Hi. Thanks for your query. Noted the history and understood the concerns. Pain in the center of the upper abdomen, nausea, feeling like going for motion but feels unfinished that is not clearing completely. All these symptoms are most probably due to gastroenteritis of chronic nature and need thorough investigations as follows: Tests of stool, blood and urine. Upper GI Endoscopy. A trial with an antibiotic, metronidazole. Probiotics and multivitamins. Omeprazole and Domperidone as you have nausea too. See the results, if getting alright these measures may be sufficient. If there is no complete relief further investigations of colonoscopy and CT scan of the abdomen will help further. If all the investigations are normal then you may be treated as a case of IBS that is irritable bowel syndrome. Eliminate the foods and beverages that you might have noticed to increase your symptoms.