A side effect of doing yoga is that it can make you cry. Obviously, we yoga teachers don't advertise with that because it could easily be taken the wrong way. While we don't set out to make our students cry, we may sometimes welcome our students' tears. And if you've ever felt like crying during class or your eyes just spontaneously started to brim during savasana, know that that can be a blessing in disguise, and that you are not the only one.
The mind and the body are one and emotions we experience often get stored in the body: as tension, tightness, knots. We hold our issues in our tissues. When we work on opening the body, as we do in yoga, we release physical tightness and with it, the emotions that put the tension there.
What soap is for the body, tears are for the soul. ~Jewish Proverb
Sometimes we are acutely aware of what we are expressing with our tears. Sometimes we have no clue. However, if you pay attention and focus your awareness on the body part that opened, it may come to you. Soon, or maybe later that day or the next.
So if you end up crying during yoga, shower yourself with affection and acceptance and stay with your breath. You've been given an opportunity to truly release, your body as well as your mind. See it as a marker on the road of personal and spiritual growth.