My sister experienced pelvic girdle pain while pregnant with her daughter. She said it hurt to turn over in bed, to walk, and especially to climb stairs.
Her doctor told her that the pain was caused by one pelvic joint becoming stiff. This irritates the other joints. He told her if she got treatment for the stiff joint, then all the joints should start moving normally once more, and the pain would go away.
We rarely think about our coxal bones until they cause us pain. My sister was surprised to learn that there were several pelvic joints, but she’s glad that the treatment was so simple.