You had mentioned in your query that it pains more at the heel where you land, it possibly mean that the soft tissue
or bone there is injured. Since there is no obvious swelling it may not be a grievous or gross injury
I suggest you to rest the part for couple of days and take any over the counter pill which contains Ibuprofen
, thrice a day for two days after meal.
This takes two days to heal, if not you need a doctor examination.