bee bonnet → fly wall a bee in bonnet (to keep talking about a subject): She got a bee in her bonnet about the wedding until now.
a big fish (an important or powerful person): Daniel is indeed a big fish in the world of politics.
a can of worms (a complicated situation): This project in fact is a can of worms.
He got a charley horse in his leg while he was running.
You need experience to get a job, but you need a job to get experience. It’s a chicken and egg situation.