Appendix is a finger-shaped organ in your body connected to the end of your large intestine. It projects into your lower right side of your abdomen from your colon area. Medical problems can occur when your appendix becomes obstructed or blocked. Blockage can occur because of fecal matter, parasites and mucus. When your appendix becomes infected or inflamed this is called appendicitis. Your appendix does not serve a certain purpose, but can be a painful area when infected.