Some people said, just use any lubricating gels/lotions. But i said it's better to see a Gyn/Oby if she really feel hurt inside.
Last year, i had the same problem. Whenever my husband tried, i feel uncomfortable and pain.
Then i went to see Gyn/Oby, when they did an ultrasound, they found out i had a cyst in my right fallopian tubes.
Please be patient with her, and ask her to see a doctor, don't take it easy on this, it could be a minor case or a bad case. But please be sure that you will always by her side.
Just like my husband did. I have gone through an operation to removed the cyst last year. Now, i don't have any discomfort or pain whenever i had sex with him.
Good luck.