Keep your buttocks in or push your hips forward. Take shorter steps. Keep your shoulders behind the front of your waist.

Sleep on your back with something to elevate your buttocks if laying flat surfaced. Or sleep in a way tthat your rolled forward hips hold that position.

My thought is that your spine is shifted--your belly is in front of your waist. And therefore your buttocks are pushed back. Your upper body weight presses on the shifted weaker area and stomping bumping, transitioned vibrations stop at the break in fluidity of the spinal shift. Massaging just above this areaand pressing downmight begin to unlock it. A liscenced chiropractor might be in order or a bone-setter type.

I No_Know