I was given a firm little pillow, made by hospital volunteers, I remember being really sore in one spot, and holding that little pillow really tight over that area helped a lot. I used it when I coughed, sat up, or repositioned. It was invaluable at home as a prop against my tummy when I slept or had to get up out of bed, out of the recliner, or off the couch. That little friend went every where with me for at least a couple of weeks.
I would ask ahead of time if the hospital has such pillows, They often used them for open heart patients who need to support their chest incisions. If not, take something like that = the size of a travel pillow, but very firm.