Its because of the lack of muscular strength, as u walk it creates pain and swelling. You should consult a physiotherapist.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +wax therapy +some strengthening exercises will be helpful for sure.. He will help you to increase healing /muscle strength /decrease swelling /increase coordination /and balance.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no leg hanging +keep doing ankle toe movements +walk in shoes with crepe bandage.