Infection.
You could have a yeast or urinary tract infection, both easy to treat and not dangerous if taken care of right away. “A month ago, sex started to be really uncomfortable for me,” says Lesley, 24. “I assumed that the guy I had just started seeing was awful in bed. Luckily, before dumping him for lack of chemistry, I visited my doctor and found out that I had a severe yeast infection with none of the usual [white, clumpy] discharge signs.” A doctor will prescribe an over-the-counter or prescription treatment and, if you’re anything like Lesley, the sex after the infection clears should be back to “amazing.”

PELVIC PAIN
Pelvic pain during sex is not as common as vaginal pain, but is typically more severe and occurs with deep penetration, not insertion. If you’re experiencing pelvic pain, you should make an appointment with your doctor.

Endometriosis.
While pain during and after sex is a common sign of endometriosis—a disease in which the uterine lining that sheds during menstruation is trapped outside your uterus, causing pain and sometimes infertility—the most obvious sign is killer cramps. Which is why even though millions of women in the world have endometriosis, many aren’t diagnosed with the disease for years. There’s a “toughen up” mentality that some doctors have about pain,” says Mary Lou Ballweg, president of the Endometriosis Association. To better explain to your doctor how much pain you’re in, Ballweg recommends downloading a diagnostic kit from the Association’s website and tracking your symptoms. “Just don’t,” stresses Ballweg, “stay with a doctor who tells you the pain you’re feeling is ‘normal.’” Treatment for endometriosis typically starts with birth control pills and pain killers, but might also include surgery to remove the tissue.