I have this same problem! This is my third pregnancy and the tailbone pain started earlier with each pregnancy. I am almost 20 weeks and the pain is unbearable at times. If I sit on a hard chair, I use a pillow, but after 5-10 min it starts hurting again. Laying or sitting in a reclined position is the only thing that helps. I have never gotten full relief until I gave birth...I know...not very encouraging!! =/
Just keep using a pillow whenever you sit down. I wish I had more advice on to relieve it.
I also get hip and pelvic pain as well.
Yes i to have alot of pain in my tailbone around the same time in my pregnancy.very weird to start so early but it does.
sound like your sciatica babe there r braces that u can get from the doc i believe.