Pneumonia can be caused by different things, but some common signs and symptoms are coughing (sometimes with phlegm or mucus), feeling out of breath, chest pain, tiredness, fever, sweating, and chills. In children, pneumonia can also cause nausea, vomiting, and diarrhea. If you think you might have pneumonia, it's best to get medical attention as soon as possible. Your doctor can order tests to figure out if you have it and help you start feeling better!