rattle around in (someone's) mind

Translations
крутиться в (чьем-то) сознании
The thought of moving to a new city was rattling around in her mind.
Мысль о переезде в новый город крутилась у нее в сознании.
Definitions
To be repeatedly thought about or considered by someone, often causing distraction or preoccupation; to linger in someone's thoughts.