My back HAS been killing me for the past week or so, I did actually think that it's down to the putting stance and was kinda hoping that my back muscles will eventually get used to it. I did 30 min putting practice yesterday and could hardly stand up afterwards
I've cut my blade down to 32" and feel like a better putter for it.
I will say that if you are chopping length off the putter to go out and try it before adding weight to the head to compensate for the loss. I have left mine because i feel as though I can be a little more aggresive with my stroke especially on fiddly quick putts.