Discomfort in the stomach marked by symptoms of nausea, loss of appetite, bloating, belching and/or flatulence, change in bowel habits, heartburn, reflux, and/or a gnawing or burning sensation in the stomach area. Causes may include insufficient digestive enzymes or hydrochloric acid (HCl), ulcer, esophageal spasms, intestinal obstruction or other motility problem, IBS, gallstones, lactose intolerance, heart problems, or other causes.