Intense labia pain in pregnancy?

I’m 40 weeks pregnant now and I know all sorts of pain is normal and I’m sure this is but I’m just wondering what’s causing it, there’s no pain/pressure in my actual vagina but my outer labia ache so bad it almost feels like pressure and a horrible sharp ache, when I lie down it’s fine but sitting or standing is horrible after a while of being up though it’s not so bad but when I’m in bed for a bit and get up it’s almost unbearable, any ideas why or how to ease the pain?