I'm 37 weeks and I've been experiencing this painful sensation off and on (but increasing in frequency) for a couple of weeks. It's a pain that starts in my low back (both sides simultaneously) and travels up my entire back in waves all the way up to the base of my skull. When I experience it, it's nearly imobilizing. I HAVE to keep my back still until it passes (usually about 15-20 seconds). I thought it was maybe the beginning of back labor, but it doesn't happen regularly enough and if I press on my uterus while it's happening, it doesn't feel hard like it does during BH. I noticed that this last time that it happened, my belly didn't feel hard while I had the wicked back pain wave, but I did have a BH directly after the wave.  I do think it's somehow related to something happening with my uterus (or surrounding muscles) because I know I've felt this same sensation a couple of times during orgasm when I wasn't pregnant. (Sorry, TMI)
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Any ideas what it could be? Maybe something resulting from an alignment issue? It doesn't follow a pattern that I've noticed - sometimes when I'm sitting, sometimes when I'm standing.Â
