I should have done this right from the beginning, but neglected to invest in a pillow. When I finally did look into it, months after my surgery, I found a suggestion on one of the boards that works pretty well. I bought the twin size of this foam [linked below] at Walmart, cut a strip off of it and folded it into thirds and slid one of the raw edge sides into a pillow case. I still use it and think it does help. Probably not suitable for carrying around to other places, though.
http://www.walmart.com/ip/Mainstays-1.25-Convoluted-Foam-Topper-Multiple-Sizes/10055840