This has to do with positioning of the neck. Our heads are heavy; they weigh 10-12-15 pounds. It’s the weight of a bowling ball! And, if we hold the head out in front of our body, instead of resting it directly on top of the spine, it feels heavy.
In that case, all of the muscles in the back and sides of the neck, and the upper spine have to work hard to hold it up. So as much as you can when you are standing, sitting, or walking, be aware of balancing your head on top of your spine. And it’s not just a matter of pulling your head back; it’s a matter of lengthening the front of your torso.
I suggest lifting the chest as if you are zipping up your jacket. If you are reading, typing or watching the ground as you walk, try looking down with your eyes instead of leaning your head forward. Repeating the act of pretending to Zip Up your jacket will give you a new habit of lengthening your torso and balancing your head easily on top of your spine.
When driving, it’s actually nice to let your head rest back on the ‘head rest’; as long as your seat is upright it aligns your head again over your center.
Another helpful thing is to stretch your pectoral muscles often. You would be amazed at the impact this has on your neck.