is sound from the chest is because of heart problem or its just chronic pain?

I am a father of a son and he has some kind of problem relating to his chronic chest pain relief. There is sometimes a he persist of having a murmur like sound from his chest near to his heart. I took him to the clinic but the doctor was child specialist not a heart specialist, he said me to consult the heart doctor. But I am so scared about it because he is my only son and I love him the most. I need to know if any one child has suffered the same problem might suggest the solution for this issue