Back Labor???

I've been experiencing quite a lot of back pain. It started around 37 weeks. One night it was so bad, I thought this must be labor and was thinking we might be making a trip to the hospital. The pain went shooting down as far as my knees. I finally went to bed and did some pelvic rocks and it seemed to help. I don't know if he was perhaps lying on a nerve or if it was back labor, but what ever it was, was very painful!