In addition to the pain in the upper abdomen described above, dyspepsia may cause bloating, nausea, burping, and a feeling of fullness that occurs soon after eating. Dyspepsia is often confused with GERD, where acid in the stomach refluxes (backs up) into the esophagus, the tube between the mouth and the stomach. Pain due to reflux is in the chest instead of the abdomen. Causes of dyspepsia may be easy to identify in some people and in other persons, no causes can be detected.