If it's sore days later, it doesn't sound like your typical "hot foot" pain. Sounds more like plantar fasciitis or something like that. I had some bad pain out at the 5th metatarsal about a year ago. Moving my cleats helped a lot, but it took time. Turns out I had given myself peroneal tendonitis that I had to go to PT to rehab. The original cause was from some pelvic / hip issues. Hurt more when walking, but I was tweaking it on the bike. I also was just spinning then with no-float SPDs. Don't know if it was the lack of float or the size of the cleat (they were too far forward too). But I don't aggravate it or make it flare back up at all with my Keos.