Any chance it is unrelated to cycling at all?

Pains can be odd. I aggravated an old hockey injury last weekend while cycling, which I, at the time, attributed to trying out a new bike setup. Knee hurt like crazy most of the week, to the point where I almost skipped a 51 mile (already paid for) mass ride I had already signed up for this weekend. Woke up Saturday morning with some pain, just decided I'd ride and if it got bad enough I'd pull off and get picked up. Finished the ride on that same bike, went an additional 11 miles to make a metric century, and yesterday and today the knee has felt perfect.

Long story short, the issue wasn't at all what I was attributing it to.