What are choices?

Life may just be an infinitely complex string of dominoes with your "choices" already decided as a result of innumerable interactions all the way down to the interaction of atoms. If it is, then nothing really matters and there is no reason to worry about it. But if it is not, then there must be some physical evidence of free will in the physical world. Perhaps the seemingly chaotic nature of quantum physics is a physical manifestation of free will.