If you have symptoms consistent with indigestion (dyspepsia) after meals, underlying gastritis may be the cause. Dyspepsia may present as upper abdominal pain, burning, or discomfort; abdominal fullness, bloating, or distension; upper back pain; reflux; heartburn; frequent burping; and nausea or vomiting. An accurate diagnosis, however, will require further evaluation, including an endoscopy.