1) Immediate pain: starts right after consumption of acidic food. It is caused by acidic substances from food irritating esophagus.
2) After meal pain: starts after heavy meal when there is too much food in the stomach and stomach acid refluxes back to the esophagus.
3) Alcohol/spicy or bitter food related delayed pain: starts several hours after alcohol/spicy food consumption. My guess is that alcohol causes some kind of delayed action when stomach starts actively producing acid several hours after consumption.
4) Chocolate/caffeine consumption heartburn pain. Starts when you consume some chocolate or caffeine late in the evening and lay down later. Heartburn happens because chocolate and caffeine relax the valve between stomach and esophagus and let acid get into esophagus.