obviously the answer is
have a check by the doctor,
have hormone blood test to see if you need hormone increase.
Have gynaecologist check your vagina and clitoris.
Consult a sex therapist.
Reduce stress and coffee and drugs, get fit.
There is no simple answer and the internet has not helped us here, my girlfriend is at stage one, getting blood tests, to her knowledge she has never had an orgasm in her life and feels nothing. I am above average sized in penis and sometime have sex for several minutes. Always she feels nothing, does not even produce myconium, she says she is broken. This affects all aspects of her cosmetic, from the way she dresses to her feelings for me. I am doing what I can to be supportive. Cheers.