I did all those test with a lung specialist. They found nothing.
The inability to take a deep breath may be ". .in the head", but at the same time, may not be an emotional or behavioral health problem. On the other hand, the feeling of what constitutes a deep breath varies significantly from one person to another and this relates to the nerve feedback signals we get from any number of sites, within the respiratory system. It would be important to determine if your inability to take a full breath, or to feel that you cannot take a deep breath, is on this basis and just your perception of not being able to take a deep breath, vs. the problem relating to some degree of respiratory muscle weakness.
Complete pulmonary function tests (PFTs), including the determination of lung volumes and inspiratory pressure could help to clarify what's going on. You might want to discuss this with the lung specialist.