Monkey on my shoulder
What does the term I have a monkey on my back mean?
"Get this monkey off my back!"... to stop a bad habit; to be rid of a problem or hang-up.
I have to get this monkey off my back. I have to stop gambling.
No idea on origin though.A Monkey on your back is an addiction. Like h****n is the monkey on an addict's back.
There is an expression used in the UK police that an unwanted responsibility is a 'monkey on the shoulder' which you can try to get rid of.