only your girlfriend could possibly answer this question but clearly she is having some issues associated with your sexual intimacy. there can be many reasons and some may be deeply private. for instance if she had a past experience that was troubling to her like a prior molestation she may have difficulty. she could have some underlying fears of getting pregnant getting an std or she may be just frightened about sex. if possible she may benefit from discussing this with a counselor or you can try talking with her. i would suggest that you be very gentle and understanding and not push her to be more sexually involved than she is comfortable doing. back off for a while and allow her more time. go slow.
why is my gf so sensitive that when i touch her anywhere she gets uncomfortable & loses any desire to get intimate? . when we get intimate my girlfriend sometimes loses all arousal because when i touch her it feels uncomfortable on her skin--she has also never had an orgasm. if we move too fast at first it hurts her (even with lubricant) but if i increase foreplay she loses arousal because touching her body anywhere makes it uncomfortable for her.