The phrase “the cough went to the lungs” usually signals concern for lower respiratory tract involvement. Warning signs include shortness of breath, rapid breathing, chest tightness or pain, wheezing, persistent high fever, and increasing or worsening sputum. On examination, clinicians may hear crackles or other abnormal lung sounds. Definitive differentiation often requires clinical assessment and, when appropriate, imaging such as a chest X-ray. Note that cough from a simple upper respiratory infection can last 1–3 weeks and does not automatically mean pneumonia. Low oxygen levels, marked fatigue, bloody sputum, chest pain, or chronic disease should prompt timely evaluation.