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

The idiom "breathe down one's neck" is believed to have originated from the literal act of someone standing so close behind another person that they can feel their breath on their neck. This phrase is used in various contexts to describe situations where someone feels closely watched, monitored, or pressured by another person or group. It is often used to convey a sense of discomfort, unease, or intrusion.