Pain in Pelvic area

I had a very terrible pain in my pelvic area at work. It felt like a tightening in my vaginal area. It started about an hour into working and lasted about 2 more. Standing made the pain worse. I had to pee; a lot, though I think it was in my head so I could get off the sales floor. I left work to go to urgent care. When I got to urgent care, it seemed to subside in the office. They took a urine sample and it wasn't a UTI. The doctor told me to go to the ER or an obgyn to get an Ultrasound. Has anyone had a similar problem?