Pain on outside of L foot on insertion of peroneal tendon to 5th metatarsal. Initially thought it might be a stress fracture, but had a negative x-ray. Took a week off, but still sore at the end of it. Became very painful to walk on, but started to clear up after 2 weeks off running.
Had to stop walking around and give it proper rest for a few days. The niggle lasted for a while, but regular stretching and manipulation got rid of it in the end.