It could be a number of things! What type of pain is it? Is it just cramping, or a sharp pain? It could be from ovulation, you could have a cyst, or an infection.....Hard to tell!

This could be a lot of things, or nothing at all. You should see a doctor immediately if pain persists; it's the only way to figure out what's going on.
If you are having sharp, persistant pain, it could be a sign of a number of things: appendicitis, ectopic pregnancy, ovarian cyst... The only way to know for sure is to see a doctor, just to make sure. And don't chance it!
More than a year ago, I started having terrible, sharp pain in my abdominal region...I had no clue what it was, so I was told to go to the emergency room.
After numerous tests ( including blood tests, ultrasound, you name it), they finally did a cat-scan and found out that not only did I have appendicitis, my appendix burst and I had to be rushed into surgery.
Not to scare you, but just note: your symptoms could mean nothing at all, or a number of things. The doctor is the only one who can know for sure.