Just as grown ups react differently to pain so do babies. I think your idea
of *shut down* is on the mark. I would strongly advise not stressing the
infant. As for the tylenol, it might make the baby more sleepy and I would
really hesitate recommending it for a newborn without the physician's input.
(tylenol made my kids sleep like crazy!) Alson with the fx clavicals, the
babies change dramatically once it is stabilized.
Sometimes when mothers don't follow our orders we get upset and worry about
their non-compliance. If the baby's clavicle fx'd, the delivery was
traumatic. Maybe someone needs to look into mom's level of pain. Could it be
she doesn't feel well enough to nurse or is in pain?  If so, relaxation techs
and alt. positions for feeding, perineal soaks, pain meds, etc. may help her.
I had moms so worried about taking anything while nsg that they are immobile
with pain.