Ovarian Cyst.
Cristina, 27, felt sharp, stabbing pain on her right side every time she and her fiancé had sex. “I chalked it up to the stress of planning my wedding,” says Cristina. But the culprit was an ovarian cyst: a painful, fluid-filled growth on one of the ovaries which usually goes away on its own and most commonly occurs in women ages 20 to 35. (Smokers beware: You’re twice as likely to develop an ovarian cyst.) Cristina’s doctor checked the cyst with an ultrasound, recommended she take Ibuprofen an hour or so before sex and then rechecked her a couple months later to make sure the cyst was gone. If a cyst doesn’t go away on its own, it may need to be surgically removed before it bursts or “pops”—which can lead to infection and infertility. And if you suffer from frequent cysts, your doctor may put you on the pill or change your birth control to better regulate your hormones and keep you cyst-free.

Cancer.
If you have pelvic pain, don’t think the worst. “It is very unusual for a young woman to have a malignant tumor,” stresses Dr. Hutcherson. But although the likelihood of having ovarian, uterine or cervical cancer is slim, it’s something to ask your doctor about if you’re experiencing pain and irregular bleeding. More likely, the pain is resulting from a more common cause like one of the ones listed above.