Ladies, have you ever found yourself gritting your teeth instead of sighing with pleasure during sex? Guys, have you ever noticed that your partner seems disconnected--or not as into it as you are? It could be because the love you're making together is painful for her. In their new book "When Sex Hurts," the authors - two physicians and a psychologist -contend that approximately 20 million women in America suffer from painful sex and that more than 40% of them do not seek help due to feelings of shame, embarrassment, confusion, and the belief that it's normal for sex to hurt. Until fairly recently, even many doctors believed that painful sex - also known as dyspareunia - was more of a psychological issue than a physiological one, and often prescribed anti-depressants or numbing agents, rather than dealing with the real, and all too common, underlying causes. But according to sex educator Emily Nagoski, author of the "Good in Bed Guide to Female Orgasms," most women commonly experience pain because of lack of lubrication, resulting in friction. "Not enough foreplay or a lack of correlation between mental arousal and physiological arousal or hormonal changes can all result in tearing and irritation." According to results from the recent National Survey of Sexual Health and Behavior by researchers at Indiana University's Center for Sexual Health Promotion, nearly 1 in 3 women--or 30 percent--experience pain during sex. In comparison, only about 5 percent of men report having painful sex.Sex researcher Debby Herbenick, PhD, believes that a portion of these women may have vulvodynia, a condition marked by chronic vulvar pain, or other medical conditions contributing to painful sex. One thing is clear, though: Sex shouldn't be painful. "Young women often get the message that 'sex hurts,' so they go into sex expecting some discomfort or pain and not necessarily telling their partner or healthcare provider or even their best friends that sex hurts," says Herbenick. "There's some level of 'sucking up the pain' that women go through. Men may take physical hits on the sports field more often than women, but our data suggest that women take more hits in the bedroom than men." Fortunately, there are simple fixes for most of these causes. Here's how to get comfortable when you're getting hot and heavy. * Keep communicating. Men don't always understand why a woman isn't as aroused as they are, but most women won't offer up that information without being asked. The key to good sex is to talk about it. Guys, ask your partner if what you're doing feels good--and ladies, be honest when you answer. No woman should have to grin and bear painful sex, and especially in our age of Internet porn, men need to know that painful sex is anything but pleasurable for a woman. * Focus on foreplay. It typically takes women longer to get physically aroused, and foreplay can help with that. Not only can foreplay enhance vaginal lubrication, but it can also help pull the uterus upward, making more room in the vaginal canal and decreasing the chances a man will hit his partner's uterus during deep thrusting, explains Herbenick. * Enhance natural lubrication with an artificial lubricant. Personal lubricants are more popular than ever and can help immensely with painful sex, especially if the underlying issue is vaginal dryness. Water-based lubricants are often the gentlest formulas, so it's best to start there. * Switch things up. Some sexual positions can be more painful than others. In general, positions that allow a woman to control the action--like woman-on-top--tend to feel more comfortable. Experiment to see what works for both of you. * Create a buzz. More studies are needed, but some research suggests that vibrations may help decrease genital pain for women. Shop for a vibrator together and look for those designed to stimulate the clitoris. * See your doctor. If discomfort persists, make an appointment with your gynecologist to determine whether you have vulvodynia or another cause of painful sex. Says Nagoski "If you had pain your elbow every time you threw a softball, so intense that you had to stop playing the game, you'd see a doc, right? If your stomach hurt so badly after every meal that you had stopped eating, you would seek medical attention, yes? So why, if your genitals hurt with penetration, often so much that you were disinclined to have sex, would you not mention this to a medical provider?" Sex doesn't have to hurt. But only through communication can you start taking away the pain--and adding back the pleasure.