My Teacher often spoke of the Mindbody connection. In fact, he coined the phrase as one word, because the two are interconnected. Let's look at that.
When you feel happy, you feel it in your body. Your chair does not feel your happiness, your pillow does not feel your happiness, your body does. When you feel joy, you feel it in your body. Your car does not feel your joy. Your kitchen does not feel your joy, your body does.
When you feel angry, you feel it in your body. Your couch does not feel your anger, your computer does not feel your anger, your body feels your anger. When you feel sad, your table does not feel your sadness, your fork does not feel your sadness, your body feels your sadness. So, what we feel in our emotional body, we experience in our physical body. That's the mindbody connection related to our emotions and our physical being.
Now, the feelings of happiness, joy, love, satisfaction, are positive emotions, and the body does not tighten up to deal with them. We tend to just experience them for what they are. Positive emotions are light and feel good, so we seek to feel them again and again. True?
However, the feelings of anger, frustration, sadness, fear, are negative emotions, and the body reacts by tightening. This is a primitive way for the body to NOT FEEL those negative emotions. By and large, most people do not want to feel these emotions. So we tense to not experience them.
One of the things I find most beneficial about stretching is how it releases the tension in the body for whatever reason it is there. Whether the tightness is due to an old physical injury, lack of activity, or negative emotions, it does not matter. Strectching does not care, it does not judge, it is just a wonderful method to relax and open up the areas that are tight.