The spine is connected with the flow of energy and the chest is connected with the breath. This is why these two areas are always involved simultaneously in Yoga practice; the act of breathing and movement become one.
The first thing to focus on is your posture. Your chest should be free to expand without limits when you breathe. Your spine should be stretched out and relaxed to allow for maximum energy flow throughout your body.
In the first Limb of Patanjali’s Yoga Sutras, called Yamas (restrictions), we can find Ahimsa. This term means non-violence to others and also with ourselves. This can also be translated as the universal law of love. When you apply this law to your life, aggressiveness and violence cease to exist.
Listen to your body. If something is uncomfortable, stop when needed. Also, if you would like to keep the pose but it doesn’t feel completely comfortable, you can modify it to release any discomfort. Remember, you don’t need to do every pose. There is no such thing as perfect posture; just follow the guidelines and let your body lead you.