When having intercourse, the vaginal opening is painful for many reasons: 1. When having intercourse, the vaginal wall is very stretchy, but if excessive and frequent stimulation causes the vaginal plexus to rupture, there will be a hematoma after the damage, and there may even be redness, swelling and pain. 2. 3. If you have just had sex, the vaginal opening may be painful because the vagina is too tight and not yet stretched enough for the male organ due to frequent stimulation. As far as possible, observe the situation, do not have intercourse in recent days, wash the vulva with warm water or use gynecological cleansing, disinfection and sterilization lotion for 15 minutes every day, and apply erythromycin ointment on the vulva, observe for 3-5 days, as long as it slowly improves, it will not affect your health.