Does this sound like a pinched nerve? Overhead press/ power-cleans.

I've been doing SS 3x5 for the last couple weeks and have progressed to about 125-150lbs all around. Recently in the past week or so, I've had a weird sensation when doing a working set of power-cleans and the overhead press. It feels like a tingling, electric pain that goes from my lower back/butt down to my feet. The sensation stops as soon as I put the bar down, and so far has never happened when doing any other exercise. Is this the product of poor posture, or should I look into visiting my doctor? Admittedly, I don't have the best ethic when it comes to stretching either, which I'm not sure is to blame, but could be exacerbating the problem. Any help would be great, and thank you guys for all the excellent material and inspiration you offer on a daily basis.

EDIT: When I think about it, I'm not even throwing around that much weight right now. Its been quite a while since I've lifted regularly, and I wanted to steadily increase the weight so that I don't burn out. It just gotten into my head, and I'm a bit worried that it will get worse as I keep putting more weight on the bar.