Hi, I m doctor Suela! Thanks for asking HCM! More than half of all children have a heart murmur sometimes in their live and most of these heart murmurs don t mean that anything is wrong. Doctors call these functional normal murmur.They are caused by blood rushing through the valves in a normal heart.One common type of normal murmur is Still s murmur ,this murmur is most often heard in healthy kids 3 to 7 years old.A normal murmur can get louder when the blood flows faster through the heart, like when kids have a fever or run around. That s because the activity makes the heart pump more blood. But even though most murmurs do not mean that anything is wrong, sometimes there is a heart problem that causes the murmur. The heart may have a hole in it, a heart valve may leak, or a valve may not open all the way.Your child has this heart pain that makes doctors suspect for a problem with the heart. So you will need to see a pediatric cardiologist. The pediatric cardiologist will ask your son questions about short of breath, chest pain, felt dizzy, or fainted. The doctor also will listen to his heart with a stethoscope, check his pulse, and listen to his lungs. Sometimes he might want you to get a chest X-ray to see if the heart looks bigger than normal. You also might get an electrocardiogram (EKG), which measures electrical activity of the heart. None of these tests hurt. The heart murmur doesn t have any effect. But if this murmur is caused from a problem with the heart, it might have effects in the future for your child s heart leading to cardiac insuficiency! I hope my answer was helpful to you! Thank you!