Gastritis, or inflammation of the lining tissues of the stomach, can be either acute (coming on suddenly) or chronic (causing symptoms over a long period of time). Symptoms include upper abdominal, or epigastric pain, and burning and heartburn. The pain may get worse with eating. Nausea and vomiting sometimes occur along with the pain. Symptoms of chronic gastritis include feelings of fullness, nausea, flatulence, weight loss, and vomiting. Bloating, belching, and loss of appetite are other common symptoms.