Are you a belly breather or chest breather? Put one hand on your chest and the other hand on your belly. Notice what hand rises when you inhale. Babies and relaxed individuals are belly breathers.
Chest breathers may have had a trauma or traumas in their past that caused them to become chest breathers.
Proper breathing starts in the nose and then moves to the stomach as your diaphragm contracts, the belly expands and your lungs fill with air. “It is the most efficient way to breathe, as it pulls down on the lungs, creating negative pressure in the chest, resulting in air flowing into your lungs.
This is a good one on how to belly breathe:
This is a good one on how to expand your lungs: