A good pillow must support your neck's natural back-to-front curvature when you're lying on your back as well as keep your head and neck straight while lying on your side. I have, and often recommend, the My Pillow Premium (https://www.mypillow.com ). These should only be purchased online where you can select the one designed most specifically for your body type.
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A Full Body Pillow (http://amzn.to/2ez64x1 ) is very long and, by placing it behind you, helps keep you half way between your back and your side. This helps relieve shoulder pressure and may also help lessen snoring problems.