She is 38 weeks and she is having pain in her vagina. It is been going on for 4-5 days, what should I do?

Take her to a doctor that would be the first thing, it could be the sign of her miscarrying.

At this stage of her pregnancy she'll be very uncomfortable. She's almost ready to give birth.

Any time you're worried, the doctor is your best bet. At this stage of her pregnancy she should be seeing her OBGYN weekly. Bring this up at her next appointment.

Good luck and congrats on the upcoming birth of your child.