What Causes A Severe Sharp Pain Near An Ovary?

I have been having severe sharp pain near my right ovary that feels more painful when I sit down. This has happened a couple of months ago but this time it is much worse and have been hurting all day. It gets very sharp off and on but it constant. Any ideas of what this could be or if I should go to the hospital or can it wait? I am 28, 149lbs, and have had no problems in my medical history...