Emotion is a physical event. When it is not allowed to finish, the body keeps the unfinished part.
Every emotion is a full-body response: a surge of chemistry, breath, muscle, and impulse — to cry, to speak, to push away, to run. When that response can complete, it passes through and the system resets. When it cannot — because you had to stay composed, because it was not safe, because you were a child and there was no one to receive it — the response does not disappear. It gets interrupted, and the nervous system stores the unfinished pattern as tension, held breath, and a low permanent bracing you eventually mistake for your personality.
That is what people mean by “stored emotion”. Not a mystical deposit, but an interrupted physical response the body is still waiting to finish. Releasing it is less about understanding why — most people already understand why — and more about giving the body the conditions to complete what it started.