strange as it sounds I have the same experience. Some so called acidic foods don't create any problems (pineapple is normally fine) whereas oatmeal (usually, but not always), crackers, biscuits, cake, sometimes bread causes burning. I think you should just find what foods work for you and go with that and focus on the lifestyle thing to help minimise symptoms.. If it feels ok to eat it, go ahead and eat it - listen to what your body likes - if it not burning, it is not doing harm. Note: I agree about the price of these drugs - that is a major disincentive to continue them.... and incentive to find some other way to manage - but unfortunately drugs may need to still be a long-term consideration in the overall management.
Pineapple and papaya both have enzymes which are known to aid digestion. The enzyme in pineapple is called bromelain, and the enzyme in papaya is called papain. Bromelain and papain both can be found in health food stores. In addition, they both reduce inflammation. My chiropractor recommended the enzymes for bursitis I was having in my shoulder, and they really worked!! Not as strong as ibuprofen, but still, bonus points for being a natural product that actually works... Anyway, not all edible "acids" are the same, so our bodies see pineapples and grapefruit as different for example, and respond differently. Also, according to recent research, the reduction of acid levels in the stomach can interfere with the body's absorption of calcium -- a certain level of acidity is required for the calcium to be accessible. Women who are menopausal or perimenopausal should take note since this can increase the risk of osteoporosis.