Indigestion is a gastro-intestinal disorder that is characterised by pain in the abdominal region.The intensity of ailment ranges from just gas to upset stomach. Symptoms The common symptoms for gas and indigestion are belching,flatulence and abdominal pain. Root causes One of the main causes of indigestion is production of gas in the stomach due to food sitting in the stomach for too much time.Other causes include the insufficient supply of stomach acids and digestive enzymes in the body.