I get these all of the time in my genital area. For me, they are my first sign that I am gearing up for a flare. During a flare, I get lots of them. They are like boils or sores.
My GI decided that they are just another way my Crohn's manifests itself. I have no idea if there is scientific backing for that but I can tell you that I will have a sore down there and within 3 days of a Remicade treatment, they went away. Now the same thing happens with Humira! Within days, they are gone. So I am convinced they are Crohn's related, too.
I've had some that truly disabled me from walking, sitting, laying, etc. I've had some pop on their own, others go down on their own. I've been checked for Bartholyn Cysts and it's not that. I treat with hot compresses and heating pads, plus hot baths. And pain meds.
Oh - and I go commando and in skirts as much as possible during those times. The more air gets to them, they better then feel and heal (per my GYN).