I am not a doctor but this sounds more like vaginismus, which is involuntary tightening and surgery is not used because it is like clenching a fist, you would not have surgery on that.
A curse could cause this, it is the female equivalent of erectile dysfunction.
I vote Hathor, she is a very loving goddess and very powerful as well:
If you cannot have a shrine visible, just use her image from this page: Hathor - Wikipedia
Speak to her in your mind, she is a powerful goddess and can hear you.
Fantasy without touching yourself may help, imagine penetration being simple and enjoyable, try to lose yourself in the imagination of it.