Complaining of fever & cough

A 57-year-old male presents to the office complaining of fever & cough. He states he felt healthy four days ago, then on the following day started to feel feverish and coughed up yellowish-green phlegm the next morning. His symptoms have progressively worsened. He also mentions right side chest pain when he takes a deep breath. He states his wife was sick with milder similar symptoms one to two weeks ago. PMH: HTN & arthritis. Medication includes metoprolol and celecoxib. Smokes about a pack a day of cigarettes but denies ETOH or illicit drug use. No allergies to medication.

What is your working diagnosis and provide 3 appropriate differential diagnosis and justify your choice of differential diagnosis.

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