Very painful, very low in the back, around the coxyc bone and a bit above, DD was posterior, and I found I got relief having it rubbed, didn't have time for a heat pack, but I reckon that would have been very effective as well.

I never really got much pain in the front at all, my belly tightened but the pain was clearly only in my back.

Will be thinking of you hun and if this is everything starting, wish you all the very best for a lovely birth