Sore vagina?

I'm 36 weeks although my new obgyn thinks I may be two weeks ahead. At Dr apmnt yday I measured 1cm dilated, baby is 7lbs 7oz. For over a week now I've noticed inside of my basins is sore, almost like a bruised feeling especially when I go to sit up. Today it's much more noticeable. Also, twice today, within 10min i had a braxton hicks that i could feel in my lower back.Is this a sign off further dilation or labor coming soon? My original due date was 9/08, but based on babies growth as of yday, sonographer stated my due date could be more like 8/23. What do y'all think? FTM here. Also, its def not from sex lol I haven't been in the mood for that lately.