I'm an ex-smoker, having smoked about 510 cigarettes a month for 56 years, and I quit just a month ago. I'm really worried because I'm experiencing chest congestion and I'm producing sputum, though it isn't thick. I'm also noticing mild labored breathing whenever I exert myself. I have a chronic dust allergy, and my recent chest X-ray showed I have mild sinusitis. The main worrying sign right now is that I hear a low-pitched whistling sound when I breathe in. Can you please advise me on how I can help heal my lungs from all the damage over the years?