Maybe your flora is off and you have yeast or bacterial vaginosis? You should see a doctor for diagnosis.
Have you started using a new soap or shaving cream in the shower? Could just be a sensitivity to that.
A few more details would help, but yeah, if you've had sex, especially if rough or a long duration or with some unnatural sex tool, that could do it. You may have a reaction to anti-sperm lubricant that most condoms comes packaged in if you used one, and/or, lots of people are sensitive to the chemicals in sex lubricanst too, very unnatural stuff. take care, April
Have you recently had sex?