I agree it is issue with lumbar area. A similar incident happened to me 20 years ago which took me several months to figure out. I was walking down carpeted stairs in my socks and half way down I skidded over several steps on my coccyx bone. I saw I was initially ok enough to get up and felt ok. Fast forward about a month I started feeling pain in my vaginal area enough to go to a gynecologist but everything checked out fine. I never connected slipping on the stairs with this new pain since a month had passed. I then started getting pain down my right leg and went to a chiro who took X-rays and said I had a slight herniated disc. After researching further I read an article that lower disc issues can cause referred pain in vaginal area and with urinating and bowel movement discomfort. Have you had any falls or something happening involving your back, or even sitting. I find if I sit too much, my butt and leg acts up to this day.