I am sorry to hear about your medical problems. Probably the infection is not yet under control. If you have bronchitis then often there is a feeling of inadequate breath due to spasm of airways. Please consult your doctor. Maybe taking a bronchodilator may help. Do deep breathing exercise and blow into a balloon. This will help dislodge any mucus and also help you breathe easier. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.
Maybe it can COPD or emphysema. Your lungs have no oxygen and your body have more co2. If you smoke, then first of all stop smoking. Consult it to your doctor and follow a proper meal plan. Try to notice symptoms of COPD, as lung irritation, family histories and by diagnosis result.