Noon,
Thanks for the question.
I have never heard of the diagnosis of pectus excavatum being made by chest x-ray -- it is usually apparent on physical examination. While it can be associated, in severe cases, with altered breathing mechanics, it is not a condition that typically affects the heart. In fact, all "pectus excavatum" means is that the chest wall/sternum is sunken in. If this was not noticed by your doctor, then you have a mild case or he/she never examined you.
MurmursHeart murmurs and other sounds can be caused by many things, some of which are totally
benignBenign ear cyst or tumor
Benign positional vertigo and others of which are not. Sometimes doctors cannot even agree if a murmur is present or not. The bottom line is that an echocardiogram is one of the more definitive tests upon which doctors rely to examine the function of the heart. The echo is certainly more reliable than the physical exam of the heart.
With all that being said, you will have to decide whether to seek a second opinion or not.
Hope that helps.