What is a hernia and what causes it in the stomach?

Hole. A hernia is a hole in the abdominal wall or diaphragm through which intra-abdominal organs may pass. I the stomach is involved, it is usually a hiatal hernia, and may cause gerd symptoms, chest pain or difficulty swallowing. See a general surgeon for a consultation if your concerned.
Weaknerss. A weakness or hole develops in the fibers that hold a person together. Most common hernias are in the groin or umbilical region. The hole or weakness allows internal structures or fatty tissues to protrude outward, and a bulge may become visible and discomfort may occur at the hernia site.