Hiatus Hernia is when the stomach bulges up into chest through the hiatus opening in the diagram. When food drops down into the first part of the duodenum the pylorus valve should open, when the food goes through, the valve should close again. This valve can get stuck open or inverted which then causes acid reflux, heart burn and or food to get stuck. A hiatus hernia can be the cause of false heart attack symptoms. It can also effect the diaphragm which will not allow you to take deep breaths or cause a sharp pain on the right side of the mid back area.