Okay - Thanks, Knot, I may PM you for more info.
One thing that may or may not be relevant: since I started riding again this year after my "break", I have been standing a LOT more on the bike. I'm not sure if it's compensating for having lost muscle strength while being off the bike or what, but I've gotten sort of accustomed to it and am out of the saddle a lot more, especially for climbing. So maybe that's aggravated or highlighted some sort of weakness/imbalance.