You had a jump followed by pain in your heel with swelling below ankle.This could be due tw reasons 1) injury
to the ligaments of ankle joint which called as joint sprain
or 2) Due to crack fracture
of the heel bone (Calcaneum
)Pl consult orthopedic surgeon and have x-ray of the foot done to rule out any fracture.If it is a simple sprain take pain killer and rest for couple of days.and immobilize the Jt by tight crape bandage applied to ankle Jt.