Your lady parts will thank you for reading this.

There’s the kind of down-there pain that follows over-zealous sex—but then there are other types that are a bit more serious. And unlike diagnosing, say, high cholesterol, identifying what's causing your hoo-ha to hurt isn't always easy. Mary Jane Minkin, M.D., clinical professor of obstestrics and gynecology at Yale School of Medicine, explains six of the most common causes of below-the-belt pain—and what to do if you experience these symptoms.
1. Herpes
No one wants to
believe they've contracted an STI, but according to the Center for Disease Control, about one out of every six American adults will get it in their lifetime. "Patients will call me at 1 in the morning and say, 'I found a lump on my bottom,'" says Mary Jane Minkin, M.D., clinical professor of obstestrics and gynecology at Yale School of Medicine. "My first question—after I groggily wake up—is, 'Does it hurt like a son of a bitch?' If the answer is yes, it's likely herpes. And if the answer is no, it can't be herpes." Visible blisters and intense pain accompany the STD. If you spot a bump or blister down below that doesn't belong, contact your ob-gyn immediately. While there's no cure for herpes, your doctor can start you on medications that will reduce your frequency of outbreaks and help you manage your pain.

2. Yeast Infections
"While these don't usually give you pain, per se, they can make you feel dry and itchy in the vagina, which some people will interpret as pain," says Minkin. Chances are good—three in four, in fact—that you'll experience a yeast infection in your lifetime. While you can treat a yeast infection with OTC medications (and may choose to if you've experienced this type of infection before), it's best to seek a doctor's opinion if this is your first time dealing with the condition. Your ob-gyn will perform a pelvic exam and prescribe you an anti-fungal cream to use until your symptoms are gone.
3. Vaginal Dryness
You may think this is only a problem for post-menopausal women, but you’d be wrong. Thanks to low-estrogen birth control pills, many young women experience vaginal dryness, too, which can make sex uncomfortable and even painful. "Estrogen is a moisturizer," says Minkin. "So if a birth control pill is low in estrogen, your vagina's moisture will also be low." If you feel like your va-jay-jay doesn't lubricate the way it used to, it might be time to check in with your doctor. "It's an easy fix because we can treat you with topical estrogen or put you on a higher-estrogen birth control pill," says Minkin.
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4. His Penis
While you may be inclined to blame your own anatomy, Minkin would encourage you to look at your partner, too. "Is it really pain in your vagina that you're experiencing, or is it pain during penetration—something you feel inside your belly?" asks Minkin. "It can be very hard to differentiate." Larger men can be, er, difficult to take in—and it may be time to switch positions to something more comfortable. If you're confident this isn't the issue, read on …
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5. Endometriosis or Pelvic Inflammatory Disease
If you have pain during penetration and your period, your symptoms may be pointing you toward endometriosis (when the tissue that lines your uterus grows in other spots) or pelvic inflammatory disease (an infection of the female reproductive organs). "For both of these, a patient might say that she has pain in her vagina, but when I examine her, I'll press my abdominal hand down and mash on her ovaries, and that's when she'll say she feels pain," says Minkin. Another symptom of these conditions? Excessive bleeding when Aunt Flo is in town. (So fun, right?) After a pelvic exam and ultrasound to determine whether you're suffering from one of these conditions, your doctor will likely put you on a course of painkillers and hormone therapy.
6. Vulvodynia
"About nine percent of women will have this kind of pain in their lives," says Minkin, describing the discomfort as occurring during penetration or even when you're inserting a tampon. For some women, pings of pain are spontaneous and unrelated to sex or touching the area in any way. "It's mysterious in that it can come and go," says Minkin. Doctors who diagnose vulvodynia will often treat it with topical medications such as lidocaine, which are also used for fibromyalgia.
Bottom line? "If everything's okay, it should be better in a day or two," says Minkin. "Almost anything, as long as it's not extraordinarily painful and it goes away, I'm not worried about. Anything else [that lasts longer], see your doctor."
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