The “best” pillow is not one universal model—it is the one that keeps your neck in neutral alignment. For back sleepers, the goal is moderate height that supports the neck gap without pushing the chin toward the chest. For side sleepers, the pillow must fill the space created by shoulder width so the head does not drop. A pillow that is too high can flex the neck forward and worsen morning pain; too low can let the head sink and strain the neck laterally. Consider shoulder width, neck length, mattress firmness, and your dominant sleep position together. If you have persistent pain, tingling/numbness, or a history of injury, selecting pillow height with a clinician or physiotherapist is the safest approach.