Understand it originates from a metaphor related to being sent aimlessly between two points. Looking for a job without a clear specialty, he felt driven from pillar to post.
Pro Tip 2/3
Negative Connotation
It usually suggests a negative experience of being unsettled or mistreated. After the team restructuring, I was pushed from pillar to post without a defined role.
Pro Tip 3/3
Lack of Control
Implies the person has little control over their situation or movements. Refugees often find themselves driven from pillar to post by circumstances beyond their control.