Splork, I was in your position a year or two ago. Went to my GP who ordered a gastroscopy examination (fibre-opticc camera goes down your neck for a look see - don't worry, you are well out!)
A rather unpleasant patch of inflammation was found, which was easily fixed with tablets, (can't remember the name, but they were prescription only, and not ranitidine). Very effective, and the sypmtoms never returned. I am told my condition could possibly have ended up as an ulcer, if left untreated. So get it seen to - eh?