Help! Contractions?

Meghan
For the past week I've been having this UNBEARABLE pain, starts in my lower back/tail bone and radiates up to the center of my back and around my waist! Had it twice within an hour the other day and a few times last night. Seems to last anywhere from 30 seconds to maybe 2 minutes. 
NOTHING I do makes it stop, I just lay down and wait for it to be over. I'm reading that Braxton hicks contractions should be painless or mildly like cramping. This is SO different. I have a fairly high pain tolerance but this pain is so severe it takes every ounce of my concentration! 
Anyone have experience with this??