Shook is the past tense of the original word, shake which means to move something from side to side. It also means to cause something to move rapidly in opposite directions.
"Mama said she didn't like the way your husband shook her violently."
Shaken is the past participle of the word, shake. It is used to describe an act of shaking that had happened in the past accompanied by a continuous action.
"I have already shaken your hand this morning."