Gas in stomach for 3 weeks and felt better now and then between the 3 weeks then 5 days it was ok again for last 3 days and pain in stomach?

Feeling gassy...: Feeling full of "gas" may reflect malabsorption of food (like gluten, lactose), intake of poorly digested food, or choosing foods known to promote gas (beans, fizzy drinks). Sometimes its more complicated--a stomach emptying too slowly, bacterial overgrowth syndrome, delayed intestinal function, partial obstruction from any cause, infection, rectum problems, and pelvic pathology outside the gut.