Back labor.

This new back pain is intense. I'm 39+3 and I am quick to be hopeful that labor is starting whenever I feel a new pain or twinge. But, even if I end up having back labor, the pain is pretty much just constant for the past hour or so. As far as I've heard, back labor is just contractions felt in your back, right? And contractions come and go unlike this pain that seems to just be here to stay. Anyone have any experience?