If photons and therefore likely all molecules stopped moving then you wouldn’t really have a way of losing heat as that eliminates conduction, convection, and radiation. But if we assume our body still works completely unfrozen then we would still need to burn calories and generate heat and without a way of shedding that what we would probably overheat and die, or depending on the limitations suffocate from lack of air if it’s all “frozen”.

Also if like everything just stopped suddenly like for example the planet earth stopped moving you would also get thrown pretty far from the rapid acceleration which could also kill you.

Basically what I am saying is it’s a much more useful question if you make the assumption that all living beings freeze but the universe doesn’t and maybe can be even better thought as plants and single cell organisms don’t freeze as that also limits the question a lot