Stomach ache or "indigestion" commonly refer to any number of gastrointestinal complaints, which often include gas (belching, flatulence, or bloating) and upset stomach.

The symptoms of indigestion or upset stomach (which are often directly associated with an individuals eating habits) may include a painful feeling in the upper abdomen, bloating, nausea, burping (or belching), dull abdominal pain, heartburn, flatuation (or passing gas), and sometimes might involve some vomiting.

“Heartburn” or upper stomach ache refers to a burning feeling that is often a result of either stomach acid being regurgitated into the esophagus from the stomach; by a condition known as gastritis (which is the inflammation of the stomach lining); or by a stomach ulcer or ulcer of the duodenum (also called peptic ulcer).