Sever's Disease is an inflammation of the growth plate (physis) at the back of then foot where the Achilles tendon attaches. The pain from this problem can present on the bottom of the foot, in the back of the heel or even in the ankle. Although it is not true ankle pain, the motion of the ankle causes the pain (since the Achilles tendon crosses the ankle and the knee joints).
Therefore, pain can even present at the ankle from Sever's Disease or Calcaneal Apophysitis.