It is important to look at the problem from different points of view. There may be a biological cause. This may be a sexually transmitted disease, a vaginal infection, a disorder of the uterus or the large intestine, an infection of the vaginal mucous membrane, a snip or a tear during childbirth and insufficient lubrication of the vagina. Men may have infections on skin anomalies to the penis, infections of the glans and the foreskin due to fungi or bacteria, a tight foreskin, prostatitis, or a low testosterone level (hormones). In women, vestibulit (an inflammation in the vagina) can be a cause of sex pain.
A medical investigation is an important step in the treatment process. The pain may be due to social causes like relational problems. Communication problems between the partners may play a role. Many people are afraid to indicate what they like in the sexual field. Psychological causes may also play a role. Since many women can't relax sufficiently, the vagina doesn't get wet enough the penis rubs against the side of the vagina, which leads to irritation. Due to the fear of pain the pelvic floor muscles are tensed too much, which causes the love play to hurt. The woman gets into a vicious circle of fear of pain, which leads to tension, the tension to extra pain and no more arousal, which leads to a dry vagina, which leads to more irritation, etc. There may also be negative thoughts and feelings about sexuality and certain harmful events may play a role.
Vestibulitus and vaginismus are other possible causes of pain during sex.
For men who can masturbate without pain, physical causes may often be excluded. Fear of pain may lead to the avoidance of the pain by not wanting to make love anymore.