[wayner]

Believe it or not, my lower back pain is usually caused by tight shoulders and shoulder blades.
Stretch those too and your lower back will loosen some.

Also, lie on a hard surface to sleep on your back. Bend your knees a bit and put pillows under your calves. The first time I tried that I lie there for a while with some meds and slowly some muscles relaxed and I felt and heard a big pop. Ahhhh relief.

That might be your best sleeping position for 3 days.
If you prefer to lie on your side put a pillow between your knees.