Definitive diagnosis

Please use the case presentation below and provide answers to the following;
1. Three differential diagnoses
2. Definitive diagnosis
3. Management plan (include appropriate treatment/diagnostic tests)
4. Indications for referral and/or consultations (if needed)
5. Health education/lifespan considerations
6. Schedule a F/U appointment
50 Y/O CM present with C/O dry cough x 4-5 months with 20 year H/O tobacco use of 1PPD for 20 years. Cough has become progressively worse over the past 2-3 weeks with yellow sputum production. Took OTC cough syrup without relief of symptoms. Afebrile at home. No CP or fatigue except with excessive coughing. No HAs or head injuries. No eye pain or drainage. No ear pain or difficulty hearing. Ocass. nasal drainage of clear mucus. No sore throat or difficulty swallowing. No neck pain or stiffness. Some SOB with excessive coughing. Excessive coughing interferes with ability to perform ADLs at times. No other household members with similar symptoms.
B/P 140/90
RR- 24
Pulse Ox check– 86% on Room Air
General: Alert, apprehensive but cooperative
SKIN: W/D with rapid recoil
HEENT: Normocephalic. PERRL, sclera clear, Bil. TMs pearly gray. Boggy, pale nasal mucosa. Oropharynx without erythema or exudate
NECK: Supple without LAD (lymphadenopathy)
HEART: Tachycardia without murmur, gallops or clicks
RESP: Distant lung sounds; positive rales at base with expiratory wheezes