The patient presents to the emergency room (ER) after having a fever for three days and new onset severe chest pain behind the sternum. The patient asks, “What is wrong with me? Do I have pneumonia? It hurts when I breathe.” Upon assessment, the nurse notes a heart rate of 124 bpm, temperature of 37.9°C, and an intermittent friction rub upon auscultation. The lungs are clear. The nurse suspects further testing will lead to a diagnosis of which condition?