Why does it still hurt after 2 years?

I got a hernia removed on August 3d of 2009, and i still get occasional pain like when i cough too hard or if im laying down on my stomach and i make any movement that puts strain on it, it begins to hurt. occasionally it happens when i sneeze too. i told my mom, and she doesnt think its important enough to go to the hospital about. So does anyone know why it would still be hurting after 2 years?