Thank you for writing JA with your question.
This could be several things.
It could be a urinary tract infection. More rarely it could be a yeast infection. If you have had unprotected sex, it could be a STD.
If you believe this is likely a urinary tract infection, increasing your fluid intake up to 8 or even 10 glasses per day of water including the occassional glass of cranberry juice (the natural rather than flavored type) can help.
If this does not decrease the problem in one day, or you think that you may have an STD then please see a doctor for antibiotics.
If you have questions or comments please reply so that either I or another expert can address them.