hi, thank-you for providing the brief history of you. As the history makes me understand that due to weakness of the respiratory system there is a production of sputum and also the mid thoracic level pain. I feel you need to do a regular breathing exercises, oxygen therapy and aerobics to improve the cardio respiratory performance. Also inhaler will be symptomatic and cannot perform well if taken for longer duration. Most of the respiratory problems are associated with the weakness of the respiratory system. Improving the strength in the respiratory muscles will help you further. In my clinical practice i have been experiencing patients complaining about the respiratory problem from longer duration and with guided respiratory exercises under a physical therapist has helped them recover well. Regards Jay Indravadan Patel