Thanks so much to everyone who is contributing to this thread, but I think I just had a revelation about the cause of the discomfort. Last tuesday I went food shopping and consciously chose to buy things that were healthier and meat-free; one thing I picked up was some organic chips and salsa, and the lid to that salsa jar was a mo-fo. I remember having to squeeze it so tight that it actually hurt my wrist & hand. I think I pulled the muscles a little bit. Then for some reason I forgot about that, and started associating the discomfort with the guitar neck, since that was when I was feeling it the most.
None of this minimizes the helpfulness or usefulness of all your comments, since I'm sure I am a candidate for RSI in the future.
