Inhale | Exhale 

It’s all going to be okay… Assuming you’re breathing right! 
Just kidding.. It’ll be okay regardless. However, the way we breathe dramatically influences our total body function and health. Breathing improperly will not only cause stiffness in the upper back, shoulders, hips, and neck, it can also decrease energy levels. The most common manifestation I see of poor breathing mechanics is neck pain and headaches. Most of us like to breathe with the muscles in the upper part of our chest and neck (instead of our diaphragm). This is especially true for those of us who experience increased levels of stress- as emotions will change how we breathe as well. Since most of us now live in a society that breeds high stress and emotion a lot of the time, it’s not surprising the most of us have forgotten how to breathe. 
If we experience stiffening in our ribcage, we will by nature also experience a tightening in our neck and hips. Where the ribs go, the hips go.. And vice versa. So now we have stiff ribs, hips, and a neck that is poorly set up to absorb the force of our heavy heads bouncing around. 
Try this. Lay on your back with your feet resting on a stool or chair (knees and hips should be approx at 90deg). Place your hands on either side of your rib cage. Take a deep breath in, and out. Did you feel your lower rib cage expand to the sides (into your hands)? No? You’re probably breathing into your upper chest and neck, then. One more time, do the same thing but move one hand to the tissue just above your collarbone. Did you feel that tissue expand with your inhale? Then you’re definitely doing it wrong. Take your hands back to your side rib cage. Now apply light pressure on either side (press in with hands) and take an inhale, focusing on pushing your hands out. Repeat this at least 10 deep breaths, also making sure to exhale entirely each time. Welcome to the wonderful world of diaphragm breathing! 
Practicing that movement multiple times a day is the first step in getting your breathing back on track. You should notice a marked difference in how your neck and upper back feel, maybe even improved energy levels and mood! Make sure when you do take time to practice this you don’t have other distractions. It takes a lot of focus to get this right!