That idiom originates from tennis. In the fifteenth and sixteenth centuries, tennis was a game played exclusively among the Aristocracies. A large area was needed to play the game, and as a result, courts were usually placed on roofs. The net was attached to a post at the side of the court that was then tied to a pillar that supported the stands on the other side of the court. And as is the case now, the idea was to get the opposing player to run rather raggedly in the hope it would mean you’d have a better chance of winning the rally. This is where the idiom to run from ‘pillar to post’ comes from.And on a side note, I was asked a few weeks ago why is ‘love’ used to denote nil or zero points. That simply goes back to when tennis was played for love, rather than for any financial or personal reward.
So two interesting tennis-based etymologies.