Are the doctors proposing a stem cell transplant using your aunts own stem cells or a donor? The process between the two can be very different, including recovery.
I went through a stem cell transplant for NHL two years ago, using my own stem cells. The stem cell extraction was through a tube inserted into a vein below my collar bone which I wore for three days and the four hour stem cell extractions were not painful with this method but I don't know which type of extraction method your aunts doctor is proposing.