Hello,
From your symptoms,it sounds like
tendonitis but ligament injury also needs to be ruled out.
Tendonitis is an inflammation of tendon. The inflammation is caused by activities involving repetitive use of the tendon, overuse of the tendon or trauma.
Apply cold compresses on the ankle and give rest to the part.Also keep the part elevated and use casts or splints.Take some over the counter anti inflammatory pain killer like diclofenac and apply some topical muscle relaxant on the ankle.