An organ with not much purpose sure can cause a lot of pain. According to the National Institute of Diabetes and Digestive and Kidney Diseases, one in 500 people comes down with appendicitis each year. “The pain is centered in the right, lower part of the abdomen. It’s associated with a slight fever, nausea, and loss of appetite,” says Dr. Philip Schoenfeld. Other stomach problems tend to get better and go away – appendicitis doesn’t.