You might have a urinary tract infection. If it's hurting when you urinate, you need to see a doctor as it could be something more serious. In the meantime, drink plenty of fluid and cranberry juice.
I'm not your doctor, so I can't tell you for sure. But it sounds like a urinary tract infection, also known as a UTI. This is a really common infection women get, especially after sex, but it’s definitely something you need to go to the doctor about.