also, don't know how you did it, but obviously lifting things the wrong way will cause the problem.
I pinched my nerve lifting heavy objects with my back, not my knees. I even are agravated it opening a stiff window.
I was in pure agony for a week, took tons of nuprin which abrely helped, hot pads helped a little. I had annoying uncomfortable numbness from my ass down my leg for weeks.
It went away all by it self after excercising a bit more.
and lots of stretching