I had a skateboarding injury at 15 and although my ankle was bad it was never properly diagnosed and turns out not I have some degenerative PTTD where I have a fallen arch and it just hurts to stand and walk. I also have issues with my shoulder blade due to carrying a heavy ass backpack and walking on one shoulder too much as a kid. Elbow popping from playing guitar too much but still popping a year after quitting.
Like none of these conditions are "major" in the adult world such as cancer and they don't really show up on exams. so they are never taken seriously.
I guess they were injuries but just chronically got worse overtime. But I used to be so healthy and its so strange now everything is just coming at me even though I am not active no more.