Sounds like chronic gastroenteritis? I had this 2 years ago, and sucks for me that it actually caused internal bleeding enough to drop my HGB around 3-ish (I was hospitalized then).

The protective lining around your stomach has worn out, which is why the doctor said it's reddish.

The most important thing is to follow the pantang (no smoke, alcohol, spicy food, greasy food, etc.) at least your stomach repairs itself and not painful anymore.

Some supplements you can take to assist in healing:-
- processed sea cucumber for medical supplement (ie: Gamatol)
- raw honey (taken before sleep)

And most important try to keep yourself away from stress.