Pain down there

Diane • DD aged 9.5, DS aged 8, and DD aged 1.5 DH aged 33 expecting a baby boy January 2017
Hi, has anyone else experienced pain around their labia/ vagina. It's difficult to describe, it's almost like a stabbing/ throbbing pain it is coming and going. It's really annoying. I feel like I need to hold on to it when it hurts, which I can't do in public! Just started last night. I'm thinking it could be to do with increased blood flow...