Pain in the back side

The last few days, anytime the kid moves or I have a braxton-hicks contraction, I get this irritating shooting pain up my back (spinal cord area) up to my neck. By the time the day is through, I am a mass of knots. So I asked the experiences of some of my girlfriends who told me I should call the doctor (and I promise I will if it keeps persisting). I did talk to my mom about it today who told that she did this when the baby was getting ready to engage. I'm thinking she's right because it's almost like the baby is on a nerve. It's one of those days when I would kill to be able to take an Excedrin Tension headache.