It wasn't until I was in my twenties that I learned this was called Precordial catch syndrome and it happens to most everyone. Every friend I've told about it was surprised, and also most knew the feeling.
I collected a growing list of strange things bodies do ever since. And now finally I made it into a little page for others to see:
https://vester.si/bodily-oddities/
It includes a form to tell me about new things, if you think they belong on the page. Feedback welcome!
V1 looked like complete Opus slop, but since I make many little sites all the time I can get it to undo a lot of them, one at a time. I just explicitly tell it the aesthetic to avoid per-element (like the famous left border), and eventually it looks okish.
I've been making this list for years as markdown files with a few sentences and links to wikipedia (or xkcd for his visual field comic), but the site is indeed made with the help of AI.
Yes, a rare but real human affliction.