I have struggled with a long term neck injury for a very long time. Standard one-piece memory foam pillows have always been way too firm for me and have left me in more pain than I can handle. I usually resort to faux goose down pillows, but after a bit of time those loose their shape. 

These pillows are great because the shredded gel memory foam contours to your neck, but isn't so solid that your neck and head aren't moving all night. Plus, you can add or remove from the pillows fill to make it firmer or softer whichever you prefer.