

You wake up, go to turn your head, and your neck says no. Or it’s fine at bedtime, but by morning it feels like it’s been locked in place. A sore neck and sleep can get tangled up, and a few things about how we sleep explain why mornings are often the toughest part.
When you’re awake, your neck muscles quietly protect it. You shift before something starts to ache, often without noticing. In deeper sleep your muscles relax much more, so your neck can rest at the far end of its range for long stretches without that protection. A position you’d never hold for 20 minutes while awake might last an hour while you sleep.
After hours of lying fairly still, joints and tissues tend to stiffen. Morning stiffness usually eases within the first half hour of moving, which is a sign your neck is ready to move rather than a sign something is wrong.
Sleeping on your front means your head is turned fully to one side for hours, close to the limit of how far your neck can rotate. For many people with a sore neck, this is the position most likely to leave them stiff in the morning.
If front sleeping is your habit, you don’t have to change overnight. A very flat pillow or none at all, with a pillow under your chest or hips, may ease the twist. Some people find hugging a long pillow helps them settle on their side instead.
What seems to matter most is that your pillow keeps your neck roughly in line with the rest of your spine. If you sleep on your side, that usually means a pillow high enough to fill the gap between your ear and the mattress. If you sleep on your back, a lower pillow is often more comfortable, so your chin isn’t pushed towards your chest.
The research on pillows is limited, and no single type suits everyone. One small study found people woke with less neck pain on a latex pillow and more on a feather one. Feather pillows also tend to flatten over time, so a pillow that suited you a year ago may now be too low. If you wake stiff after a night away, an unfamiliar pillow may be part of the reason.
Scrolling on your phone in bed, propped up on pillows, often means looking down for a long time just before you lie down. Your neck may already feel tight before the night begins. Stress can play a part too. Many people carry tension in their neck and jaw, and some clench their jaw at night without knowing.
Check how high your pillow sits under your head when you lie on your side. If your head tilts down towards the mattress, try adding a folded towel under the pillow and notice how your neck feels in the morning.