Sounds like the contents of your small intestine are back washing into your stomach. Could be due to liver and gallbladder congestion (research Liver Flushing if you haven't already). Also if food is not moving through the intestines at a good pace then that can cause things to back up due to blockages etc. Enemas would help with this and also eating more raw vegetables and soaked nuts/seeds and less cooked starchy foods which can slow down gut transit time. Raw foods pass through the system in half the time so can help to clear
Blockages and prevent indigestion. I ended up with stomach ulcers due to the backwash of undigested food from the small intestines. If this happens, reduce food intake and drink lots of GOATS milk, fresh cabbage juice (tastes awful but works), cayenne pepper and coconut oil.