What Causes Stabbing Pain In The Vagina?

I m 47 yrs old .. I m not pregnant . I do still have. Reg monthly period . I have been having. Sharp stabbing pain between my legs ... On my vagina . It only happens every few months and last about 3 hours a time full aching pain . When I take my hand an push or squeeze like kagle excercise it feels better for a few minutes . Had a pap ... All was normal . No infections ... Nothing falling out or down ... It s driving me nuts . Do you know what it could be