Why does a person feel pain when he stands on a pile of gravel than when he stands on a bed of sand?

Why do we feel pain when ants bite us?

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?

Why does a child feel more pain when she falls down on a hard cement floor, then when she falls on the soft muddy ground in the garden?

Why does a person standing for a long time get tired when he does not appear to be doing any work ?