What is the origin of the idiom "milestone around one's neck" and when to use it?

The idiom "milestone around one's neck" is used to convey a burdensome situation or responsibility. It suggests that achieving a particular milestone or accomplishment has become a heavy burden or obstacle for an individual instead of being a source of pride or progress. The origin of this idiom can be traced back to the literal image of a heavy milestone, typically made of stone, hanging around someone's neck, impeding their movement and causing discomfort.