In most of cases where is child is complaining of chest pain is of unknown etiology. Out of common causes of chest pain, chest muscle and bone pains are most likely reason of chest pain, it can be due to gastritis or lung issues also.
In only 5% cases, it is due to heart related. As with pulmonary causes of chest pain, persistent and severe chest pain, associated with fever can represent pericarditis or an inflammation in the sack the surrounds the heart.
Chest pain that occurs repetitively with exercise and symptoms of passing out with exercise can be very important. There are rare coronary artery origin anomalies that can cause these types of symptoms. Other causes can be severe valve abnormalities or hypertrophic cardiomyopathy.
In general, many of the cardiac causes of chest pain can be sorted out with good history and physical examination and simple tests such as an electrocardiogram and echocardiogram.