I have a brain injury and lost the sexual urges feeling but my body still tells me i need pleasure how does this happen and work?

Endo problem?: I wonder if your injury affected the hypothalamus and/or pituitary gland. There are certainly other areas of the brain which, if injured, could affect your sexual function. But if you've not had an endocrine evaluation to check levels of gonadotropins and sex hormones, it would be worth checking. If there's no problem there, it's possible that a psychotropic med might help (trial and error).