It could mean a lot of things,
two symptoms are often completely unrelated.
if your lower back hurts too,
it could mean that you have a kidney infection and the pain in your legs is differred from your lower back.
It could mean nothing at all too.
Do yourself a favor,
drink about a gallon of water a day and drink some cranberry juice at least two glasses a day for a few days.
If the symptoms don`t clear up,
see your doctor.
If your symptoms do clear up,
still mention it to your doctor,
there could be other things going on.