It's from hormones that are relaxing everything. They are normal and very painful. I first got them in my sleep and thought it was a dream when I woke up, until I got them later in the day.
It's called lightning crotch and it's completely normal. It's when the baby hits your cervix. I get them occasionally too.
I'm 31 weeks as well and i started having sharp pains in my vagina today. They are normal as long as you don't have bleeding and the aren't consistent. Call your doctor if you are concerned
I think I had that too. Out of nowhere they'd hit, and I'd yell out or get stopped in my tracks. I never found out what they were, and since they were never persistent or worsening over time nothing came of them. Maybe a pinched nerve or baby kicking down there? Idk...