The stomach is located in the abdomen. Pain in the stomach may be due to heartburn, acid reflux, or nausea, usually in connection with digestive difficulties. In these cases, taking antacids or proton pump inhibitors - which have the effect of reducing stomach acid - and can relieve pain. They can also be a sign of an inflammation of the stomach lining, gastritis, an injury or perforation, an ulcer, or cancer. The diagnosis can be made through the introduction of a camera into the stomach through the esophagus; this is called an endoscopic examination. If the doctor finds nothing, the option of difficult digestion is preferred.