Back labor?

Jessi

Can someone please describe back labor? Is it a constant ache or does it come and go like normal contractions? What does it feel like? Where in the back is it located? I'm a FTM and 36+6 weeks. I'm no stranger to back discomfort but this afternoon, the pain has definitely increased. I've taken a tylonal, had a warm bath, had my husband massage my back, and tried every position possible with little to no relief. It even hurts to breathe at times

Is this back labor or just normal but increased pregnancy pain?