Ditto the comment up above about the chiropractor. I see someone who is trained and experience in treating pregnant women (important IMHO) and it has made a HUGE difference. Trust me, if you have bad butt pain at this point it is only going to get worse and worse as the pregnancy progresses so now is the time to start doing something about it. Mine started right around 20 weeks too and the chiro plus some massage every now and then has really helped. I see the chiro more often though b/c it's better covered by my insurance.