You can reduce neck strain and pain by knowing where the top of the spine is.
Looking at the first photo below, this is a very common manoeuvre that most of us carry out many times a day. You may be surprised to know that the head weighs about 5kg and the further it’s moved in front of the cervical spine (neck), the more of a drag on the spine and the muscles at the back of the neck. When this is repeated over and over again, the trauma adds up and can lead to neck strain and chronic pain. The top joint of the neck where the first cervical vertebra meets the skull, is much further up than a lot of us imagine. If you place your index fingers on the bony bump just under your earlobes and imagine a half way point between an imaginary line drawn from one finger tip to the other, through your head, this is where the top joint is. Experiment with gently nodding your head backwards and forwards from this point and look down at your phone by moving from this top joint. Contrast this with leaning the whole head forwards from the lower neck (it may help to place a hand on the back of your neck to feel where you are moving from). Notice a difference in how heavy your head feels and the pulling effect on the lower neck in each position.