Pneumonia is a lung infection caused by germs. It can occur on its own or as a result of infections like influenza.<br />According to Allure, it's one of the most common reasons people end up in the hospital.<br />Pneumonia is an infection of the lungs, so it typically comes with breathing-related symptoms.<br />Coughing up lots of phlegm, shortness of breath, and sometimes chest pain due to lung irritation are common symptoms.
