I get that too, every time I walk. it's gotta b lightning crotch. it f-ing hurts!! ppl say walking is good for getting labor going but I can barely walk across my kitchen lol.
"Lightning crotch is the nickname given to a sudden and often sharp pain deep in the pelvis or vaginal area. The severity varies but most women find that it's quite painful and feels like they're being 'punched in thecrotch'."