Thanks for the very detailed answer, Sput. I always work on mobility as a warmup, but I'm sure there's always room for improvement. Unfortunately, I've been sitting more at work lately, which I don't like. Just part of the job. That may have something to do with it.
I'm also very conscious when I'm lifting on trying to have perfect form, but it very well could be that I am not moving properly. I should video my squat. I have had it analyzed by both an Olympic lifting coach and an ex- powerlifter and neither saw any issues. That doesn't mean that I was squatting perfectly that day!
Once it starts to heal back up, which I'm hoping won't be too long, I will "go back to the beginning" as they say and really work on my form.