Is this the start of labor? 36w 6d

I know what lightning crotch is and I usually get it for like 10 sec and it goes away but I'm having lightning crotch for 10-20 min now it won't go away it hurts so bad! I've tried laying down and standing and sitting but nothing helps! From the last time they checked me at 35 weeks I was 1 cm but haven't been checked since. Any advice it hurts!!