Sometimes I feel I can't get a deep breath, with a feeling of bloating esp when standing, even without excessive food intake. Panicky as result. Why?

Bloating. Bloating can contribute to being unable to get a deep breath. Think of it as reduced space for your lungs to expand. A very common cause is 'heartburn' or reflux. A simple thing to do is take one Prilosec OTC and see if the symptoms improve. It would be best for you to see you physician for further evaluation if this continues.