What is the origin of the idiom "a monkey on one's back" and when to use it?

The idiom "a monkey on one's back" is used to describe a persistent problem, burden, or addiction that someone finds difficult to get rid of or overcome. It is believed to have originated from the image of a person carrying a mischievous monkey on their back, which constantly distracts and causes trouble. The idiom is commonly used to convey the idea of a pressing issue or dependency that weighs heavily on an individual, affecting their well-being and hindering their progress or happiness.