Query about ankle sprain

Hi there, i sprained my ankle badly playing badminton. after 3 months it was still swelling up a little but i hurt it again on the stairs. now it swells on the inside of the ankle, just on the bone, compared to the other ankle with legs together you can notice the bone. I have no real pain and no problem moving about although the outside swells from time to time. any ideas what this may be, obviously something is up, what should i be thinking about doing. many thanks