I'm used to lower back pain, but lately I've been getting this weird middle back pain that feels like my muscles are tightening and not letting go. It does come in waves so I'm wondering if maybe this is a new kind of Braxton Hicks? I've had BH since 16 weeks so I'm aware of what they usually feel like for me...but this is so weird feeling. It's incredibly uncomfortable and usually happens when I'm sitting. Anyone else have this sort of pain?