Vaginismus involves spasms and tightening of the vaginal muscles, which can make sex super painful. There are many underlying causes for vaginismus: painful periods, endometriosis, trauma, pregnancy/vaginal delivery, vaginal dryness, and even recurrent or persistent vaginal infections. When these issues cause pain, then the muscles of the pelvic floor brace themselves in anticipation - this actually leads to a feeling of tightness and soreness in the area. Vaginismus is more common than you think!
Some studies estimate between 5-17% of women suffer from vaginismus. A gynecologist can do an exam to determine if there is an underlying condition that needs treatment. Treatment may also include vaginal dilators and pelvic floor exercises meant to relax, not tighten, the vaginal muscles. Often, pelvic floor physical therapy - a type of physical therapy that focuses on the muscles of the back/abdomen/pelvis surrounding the bladder/vagina/rectum - is an excellent resource to learn these exercises that relieve vaginismus. Remember, sex should not hurt - so, if it does, it is worth getting it checked out.