Appendicitis is an inflammation of the appendix, a finger-shaped pouch that projects from colon on the lower right side of abdomen. The appendix doesn't seem to have a specific purpose. Appendicitis causes pain in lower right abdomen. However, in most people, pain begins around the navel and then moves. As inflammation worsens, appendicitis pain typically increases and eventually becomes severe. Although anyone can develop appendicitis, most often it occurs in people between the ages of 10 and 30. Standard treatment is surgical removal of the appendix.