No, I'm not talking about your boss, your homework, being stuck in traffic or even all the things on your to do list. I'm talking about the tightness between your shoulders that can cause pain up into your head, down your arms, sometimes in your chest and can even feel like a sharp pain deep in your inner ear. To explain how and why this happens, let me start with an anatomy lesson. The main muscle group involved is called the trapezius. It is so named due to its trapezoid shape, like a…