Acute pericarditis is an acute inflammatory disease of the visceral and parietal layers of the pericardium, with the most common cause being viral infections. The hallmark of acute pericarditis is pain in the precardiac area behind the sternum. The nature of the pain is very sharp, typically occurring during the fibrinous exudation phase of inflammatory changes, caused by friction between the visceral and parietal layers of the pericardium. The pain can radiate to the neck, left shoulder, and even the upper abdomen. It is associated with respiratory movements and often worsens with coughing, deep breathing, or changing body positions. When fluid exudes into the pericardium, separating the visceral and parietal layers, the patient's pain may decrease or disappear. However, some patients may experience symptoms such as breathing difficulties and edema due to cardiac tamponade.