Vaginal itching, please help

I keep getting this insistent itch that won't go away until I basically itch it raw. I don't have a yeast infection or other STDs or anything like that.

Washing it with scent free soap works temporarily but not all day. I've noticed that if my pubic hair gets too long sometimes it happens but it doesn't last like this has been recently.

Sex doesn't help or make it worse. I started the other day not wearing underwear and shaving it down. The only thing with that is I'm lazy when it comes to shaving, and my fiance is uncomfortable with me never wearing underwear. He's understanding of it right now while i try to "fix" this... but it's not a permanent thing.

PLEASE HELP!!