Forward head posture is pretty ubiquitous in the 21st century. There's plenty of resources online about how to fix it from a purely physical approach, but I think the long-term solution is much more of a personal one.
Some common suggestions for correcting forward head posture include simply moving the head backward, which I feel does more immediate harm than good. If the head is forward, the shoulders are usually rounded as well (aka kyphosis). So, shifting the head back with this type of body shape collapses the breath by cutting off air flow through the throat. Another 'fix' is bringing the shoulder blades together, which most people find by arching their mid back in a way that the spine is not shaped, generating a lot of unnecessary tension and/or pain in their back and neck. I find that apporaching alignment from an energetic perspective brings faster change without ticking off another part of the body.
How does forward head posture have an energetic connection?
As the head drops forward, there's also a fold at the diaphragm or solar plexus (where the rib cage splits). From an Eastern perspective, this is where the third chakra is located. This area represents our personal power and autonomy, our sense that we have volition and agency in our life.
What causes restriction at the third chakra?
Pretty much anything that compromises our ability to truly be ourselves and love ourselves. This can be events in our past and it can also be aspects of our present life. You may have not have grown up in a family culture of complete love and acceptance for your true self. Maybe you now feel burdened by responsibility and you're unhappy in your job/relationship/life. If this rings true, you may not feel like you have personal power or ability to change the parts of your life you're dissastisfied with.
Shame shuts off flow through the third chakra and limits our ability to fully embody our power. It wasn't until coming across Brene Brown's work several years ago that I realized how much shame I've held onto--I don't think I fully understood what that word meant before reading her book. Shame=all of the ways you don't feel like you're enough. For me this came in sneaky ways....maybe I didn't say 'I'm not attractive,' when looking in the mirror, but I did hold myself to a super high standard and compared myself to my percpetion of others. Shame lies on the other side of all of that because I could never be or do enough. Finding self-love has been a beautiful thing!
Some of us self-sabotage as a part of being constricted in this area. Maybe we put too many things on our plate and have a tough time saying 'no' to commitments. Others procrastinate and feel shame for doing so. Regardless of our personal habits, we can find ourselves in the midst of a big ol' shame snowball.
So how does all this connect to posture again?
Basically, forward head posture, just like everything else in the body, is more than just you looking at your phone too much. It's also a relfection of feeling burdened and not enough.
What helps?
The third chakra is located at the diaphragm, so doing more things to connect with your breath and lift through that space will help. Here's a video to help explain that in a seated position.
In addition to connecting with your breath, start noticing how you treat yourself. Do you belittle yourself or have a harsh inner critic? Do you take on more than you can reasonably accomplish without feeling stressed? How do you approach your responsibilities? Is there a way to visualize the best possible outcome over feeling overwhelmed?
Allow yourself to feel more over thinking. We value thought over feeling as a culture and that contributes to the head falling forward--we decapitate ourselves from the rest of the body. Taking a moment to feel and appreciate something in your day can show you how much power you already have.
And that's always a good place to start. :)