"avoir froid dans le dos" is an idiom which means to be afraid, to be frightened For exemple : j'en aie eu froid dans le dos = I was really afraid. Il m'a fait froid dans le dos avec ses histoires= He really frightened me with his stories. There are other idioms with the word "froid" : Jeter un froid= It's when you are a spoilsport Ne pas avoir froid aux yeux= It's when you are brave, courageous Prendre une douche froide= it's when you have a shock

never heard about....where did you get it from ????

I've found the answer myself fret = froid and the phrase means "to fear very much"

Как камень на шее?:)