The long-form name is GERD... gastro-esophageal reflux disease. (Might be spelling it wrong.)
There is a valve (a sphincter) where your esophagus ends and your stomach begins. It should normally stay closed so that acid doesn't go back up. In people with reflux, stomach acid enters the lower esophagus which wasn't designed to handle stomach acid, and it gets burned. Over the long term, the sphincter and lower esophagus can become diseased. Some people have to get it removed. Some people develop cancer in that area.
Taking digestive enzymes can help, along with changing diet. More cooling foods, like raw veggies and their juices. Diets high in fat and sugar going to lead to more acid.