I Have Had On/off Pain In My Right Ankle For

I have had on/off pain in my right ankle for over a week now when bearing weight. I have not had any injury to it. Started off just occasional pain then would be completely fine, now hurts all the time. No swelling. Hurts to bend my ankle or put weight on it. The pain is felt in the back mostly and radiates to the top. No discoloration either.