Braxton hicks or something else??? Strange cramping sensation......?

Hi, I'm 36 weeks along and have been getting a painful cramp type pain on the entire left side of my uterus, nothing stops it, sitting, laying or walking.....my question I suppose is what could it be? It's a constant pain that doesn't fluctuate or go away, it's just there for hours, then gone again.... I have been getting other cervical pains and have started to efface and this pain is totally different to it. It's also starting to hurt when baby moves (bub is very low). I have no other symptoms, no diarhea, no discharge, not constipated.....