It's called...Symphysis Pubis Dysfunction. I had it on my third pregnancy. Extreme pain in the pelvic area when lifting your leg up, rolling over in bed, and especially when laying on your sides.
It's caused by the "widening" happening too soon.
I couldn't find anything to relieve the pain. But
It goes away right after giving birth.
I had my baby a month ago...and I feel no pelvic pain any longer
Here's a link to a page on SPD.