 [ Symptoms ] what is prostatitis [ Disease ] prostatitis is swelling or infection of the prostate gland it often hurts the prostate gland sits just below a man is bladder and makes part of the fluid for semen in young men the prostate is about the size of a walnut it usually grows larger as you grow older there are several types of prostatitis they vary based on how long a man has had the problem and what kind of symptoms he has webmd medical reference from healthwise this information is not intended to replace the advice of a doctor healthwise disclaims any liability for the decisions you make based on this information © 1995 2011 healthwise incorporated healthwise healthwise for every health decision and the healthwise logo are trademarks of healthwise incorporated