Welcome to e health forum.
It seems that you may be having a herniation at the gastroesophageal junction, which is also called a Hiatus hernia.
This condition occurs due to weakness or a tear in the diaphragm, a major muscle that separates the chest from the abdominal cavity. This herniation results in chronic gastric reflux and hence all its potential consequences of GERD - heartburn, esophagitis, Barrett's esophagus, esophageal cancer and dental erosion.
The surgical procedure used is called Nissen fundoplication. In fundoplication, the gastric fundus (upper part) of the stomach is wrapped, or plicated, around the inferior part of the esophagus, preventing herniation of the stomach through the hiatus in the diaphragm and the reflux of gastric acid. The procedure commonly performed laparoscopically has a low complication rate and a quick recovery of 2 -3 weeks.
I hope this helps.