Burning sensation in stomach after eating certain foods for few years. doctor said if it was a stomach ulcer i would have blood in stool by now.true?

Not True: Most ulcers are caused by an infection with h. Pylori. Any physician who hears your history and does not test you for h. Pylori needs to be fired.

Hard to see blood in: Blood is often difficult to see when it is in small amounts /mixed with stools. The commonest cause of symptoms like you have is acid reflux(one/ of 5 people have it). Usually it causes lots of burps and regurgitation of acid/food in the throat/ mouth. A short trial of an antacid like Pepcid (famotidine) at bed time daily might help clarify the cause. There are stronger antacids you can use, if Pepcid (famotidine) helps.