About 15 to 20 percent of individuals living in the United States have chronic abdominal pain, often of unknown origin, which is often difficult to diagnose and treat. One possible cause of chronic abdominal pain is an inflammation of the intestines, but it is not known whether the two are related. Furthermore, although overweight people tend to be more likely to have increased inflammation, it is not known whether there is a connection between increased body weight and chronic abdominal pain. This study will examine the relationship between symptoms of chronic abdominal pain and intestinal inflammation by comparing the medical test results of normal weight and overweight patients who have a history of chronic abdominal pain.