Likely cause: Dryness.
What to do: Pain is usually due to inadequate lubrication, so first try a water-based lubricant. If that doesn't help, talk to your M.D. Since levels of estrogen—the hormone that keeps the vagina healthy and moist—drop with menopause, he may prescribe vaginal estrogen (often a topical cream). You also might have a yeast infection (telltale symptoms are itchiness and thick white discharge), which your doc can diagnose with a vaginal culture. "An over-the-counter treatment like Monistat will clear it up," says obstetrician-gynecologist Mary Jane Minkin, M.D. "One-day products are generally effective, but some women get better results with three-day varieties." Finally, ask your doctor if a medication you take may be to blame. In rare cases, painful sex can signal endometriosis, a condition in which uterine tissue grows outside the uterus and forms scar tissue or cysts.