Birds hide illness extremely well, usually by the time symptoms are noticeable the bird may have been ill for some time. Any change in behavior should be taken seriously as it could be an indicator that something is wrong. What is your workplace like, is there lots of activity, sounds, smells etc? I would suggest that you find a avian vet that would be able to examine the bird, to be on the safe side. When a bird is ill it can deteriorate quickly. Sorry if this sounds scary but I would be concerned for any bird that is puffed up and shaking if the space is not cold. I am assuming that the puffing up is not the same thing you see when sleeping. How old is the bird?