After keeping the resentment bottled up for years, she got everything off her chest during the therapy session.

got 是动词 get 的过去式。 off 表示"离开、脱离"。 chest 本义是"胸膛"，这里比喻为积压在内心的情感或想法。 get sth off one's chest 是一个习语，意思是把长期担忧或愤怒的事情说出来、倾诉出来，从而感到轻松。