Why are we talking about the jaw? | Getty Images/CSA Images RF If you’ve ever taken a yoga class or gotten a massage, you may have heard that stress is stored in specific parts of the body: Emotion in the hips. Strain in the shoulders. Anxiety in the gut. And, it seems lately, particularly online, trauma in the jaw. On social media, videos abound of young women lying face up on massage tables with someone’s hands in their mouths. Labeled as a “…