Shoulder Tension

Why do humans have a tendency to “get into our shoulders?” I’ve been pondering this for a while now. When I first started practicing aikido, my sensei told me that I was “very much in my head.” These days, I feel like I’ve settled down from being in my head to more “in my shoulders.”
This seems very common, especially among beginners and in weapons training. We tend to get excited, or scared, and move up into the shoulder region. Picture yourself being suddenly afraid, and sharply inhaling as a result. Do you feel yourself suddenly rising up? If so, then you know the feeling I’m describing.
What causes this? Recently I found two pointers that may help me find out. One was my massage therapist (who also is a yoga instructor), who said that some believe humans are developing a new chakra between the throat and heart, and it may be related to this. Slightly less esoteric than this, in Dan Millman’s Everyday Enlightenment, he identifies shoulder tension as a manifestation of the inability to delegate. That one hit home with me.
Regardless of the cause, this causes imbalance (I get top-heavy) and energy depletion (where I am trying to use shoulders to accomplish technique instead of letting power flow from the legs, hips, and torso).
I am currently in negotiations with a prospective employee who may be able to take some of these daily (work) obligations off my plate. If I can successfully offload them, perhaps my shoulder tension will drop. Furthermore, my aikido may improve as a result! I am cautiously optimistic. Watch this space for details.