Shift work can be available in nearly all fields and is largely dependent on the setting that you practice in and the particular arrangement you have with your employer rather than the the field itself.
Nearly all inpatient work in large hospital settings is going to be "shift work" to some degree. Assuming there is a system in place for overnight coverage, your responsibilities will come to an end when that time comes, and you will not be responsible for call overnight. This is especially true in academic settings, where you will often have residents being the primary person on call and you, as an attending, will likely only be responsible for back-up or to be available if the resident has questions. Would you consider that shift work?
Most people consider "shift work" to essentially mean "when I'm off, I'm off." If that's your definition of shift work, I would argue that the setting that you practice in and the particular system of call coverage used by your employer will have a much larger impact on your perception of doing "shift work" than your choice of specialty. Of course, some fields are inherently going to have more call, but even that can be limited by choosing your work setting carefully.
