I work out on a regular basis consisting of squats, lunges etc. I recently just walked around a track and did 12 laps with step ups in between. I came home with a swollen inner ankle, sore to the touch as well. I never rolled it or did any injury during this session. It is now two days later and my inner ankle bone is black. and as well, the next day swelling was gone and not sore to the touch.