There are many reasons young women can experience painful penetration. Some common conditions that can be at the root of the problem for women in late teens to early thirties include:
Vaginismus: The muscles at the opening of the vagina contract, causing burning / stinging pain as an involuntary response to penetration. The contractions can make it very painful to insert a tampon, make it impossible to have sexual intercourse or even undergo a gynecological examination.
Pelvic floor dysfunction: The pelvic floor muscles—the ones you tighten when you want to stop passing urine quickly—can become painfully tight. This can cause pain with any kind of insertion.
Vaginal Infections: Bacterial, yeast, or sexually transmitted infections can cause pain during sex and usually have other symptoms, like discharge or odor. Watch out for any symptoms or abnormality and in case you feel there is something wrong, book an appointment with your gynecologist.
Hormonal birth control: Hormonal birth control pills can cause fluctuations in hormones and an imbalance of your estrogen/progesterone levels that mimic the second half of the menstrual cycle, which is a progesterone-dominant, low-estrogen state. When vaginal estrogen levels drop the tissue in the becomes dry and sex can become painful.
Vulvodynia: Chronic pain at the opening of the vagina, including burning, stinging, soreness, itching, rawness, and pain during sex.
Endometriosis: Endometriosis is a chronic condition in which the tissue that line the inside of the uterus or womb is present outside of the uterus. Endometriosis most commonly occurs in the lower abdomen or pelvis. This causes inflammation (or adhesions) which can lead to painful sex. Hormonal contraceptives limiting estrogen to prevent endometriosis tissue flare-ups, can cause vaginal dryness and pain during sex.
Congenital anomalies: Most congenital anomalies of the vagina are rare, they can include a thick hymen, a septal membrane, or a vaginal septum that that blocks the vaginal opening or makes penetration painful.