Vagina hurts when I wake up?

I would understand if it’s from rough sex or if I gave birth or something but it’s not. It happens once every few months when I wake up my vagina area feels like it’s aching, more like on the bones between my legs but it hurts my whole vagina area :( it lasts for a few minutes till I get out of bed and it goes away. It’s been happening for years. And yes I’ve been checked. I’m not pregnant either btw. It could be something as simple like sleeping with my legs spread open but I have no clue and I’m wondering if anyone knows what it can be?