Lower back pain at 10-12weeks?

When I lay flat on my back or flat on my stomach for like five min I get really bad lower back pains like right above my butt . I'm 12 weeks and its been going on since about 10 weeks I just had and ultrasound and everything came out great ? My doc wasn't very reassuring when I mentioned it to him he just kinda brushed it off . Has this happened to any of you before ?

Vote below to see results!