Not many people focus on the neck muscles. Try these if you are worried about your posture. No equipment is needed and you can do these exercises anywhere.
Tell your body what is “Normal”
If you are doing something for so long, your body learns the new normal but it doesn’t mean they are good for your body. All you have to do is to keep reminding yourself/ body of what is normal for your body. Maintaining muscle strength, flexibility is so important to achieve this goal.
Chin tuck on the wall
Standing right in front of the wall, the back is against the wall, keep the back of the head against the wall throughout the movement, then tuck the chin. You can do this while waiting for the traffic light or if you are a desk worker, you can do it anytime you feel like.
Chin tuck with quadruped position
Starting from the quadruped position, bringing the head forward first, scooping the head all the way back to the chin tuck position. With this modified version, your neck muscle has to work against the gravity that challenges your muscle more than the previous version.
Together with some shoulder mobility / flexibility exercises