Thanks ladies!
I'm going to rule out stress fractures for the moment - if it still hurt today I might think that was it, but it's fine now. Plus that sounds awful and if it is that maybe I can just wish it away. (I've decided that my family crest should feature an ostrich with its head in the sand.)
I got my shoes in 2006, and I have been contemplating a stiffer shoe. I hadn't thought about cleat placement for a long time, but that is a fixable culprit if it is. I could start there.
2001 Cannondale R500 <3
2011 Specialized Ruby Elite Apex
2021 Tangential Speedarama