Whether or not their pain has clear physical basis, an astonishingly high number, on careful asking, give history of sexual and physical abuse in childhood. I find these physical aches and pains as a substitute, arising from the factor of 'repetition compulsion', for the sexual experience itself, done in a distorted fashion, and simultaneously a self punishment for the abuse.
In my practice, on pursuing this line of thinking with my patients, I find that in an overwhelming number of cases the sexual experience was frightening, painful and humiliating. Nevertheless,
the patients repeat the experience in his or her fantasy and in extreme cases virtually every night. Its purpose is to abreact the trauma. When the patients are made aware that they are repeating the unwanted sexual trauma either in their racing thoughts/daydreams or in their nocturnal dreams, they first usually protest tooth and nail, but eventually see the correctness of the interpretation.
The relief obtained from repeating the trauma in their fantasies is meager in comparison to the punishment they heap upon themselves for repeating the experience in their thoughts. The punishment is not just for the guilt for having participated in the act - even when it was coerced, as is in an overwhelming number of cases - but it also involves punishing the perpetrator through identifying with him.
Childhood sexual abuse to females provokes thoughts/impulses/fantasies to attack the perpetrator, including a strong wish to castrate him to rob him of his penis for her own use, and a wish to have a child by him. The aggressive impulses towards the perpetrator is often discharged by turning it against one's own self and doing the suffering of the perpetrator through identification. Fibromyalgia in such cases occurs because the patient, on repeating the sexual trauma in her daytime fantasies and in her dreams, keeps her body tense. The muscles are tense because in sleep, when body musculature is supposed to be relaxed, it is not. Such patients, even in sleep, are in a state of half alertness, prepared to fight the perpetrator to void the abuse, attacking him back in the dream to avenge for the sexual humiliation.
Brain scan studies that show hypersensitivity to pain stimuli which is held as the cause of fibromyalgia does not contradict the above theory, it supports it. Childhood sexual activity is more painful than pleasurable because the body is not physiologically prepared for discharging the sexual stimulation. Also, often sexual abuse of children is accompanied by physically hurting them for sadistic satisfaction and to complete the intimidation process. Therefore, the tracts of pain are simultaneously stimulated with sexual behavior. As an adult, whenever there is any sexual arousal it immediately provokes the reactivation of pain tracts, increases muscle tension, and results in fibromyalgia.
No wonder people who have been sexually overstimulated as children avoid normal sexual activity as adults.