A murmur is only a sound generated from uneven or turbulent flow of liquids past a narrowed structure. In the case of murmurs
generated by the heart, the important thing to remember is to not focus on the murmur, but on the flow dynamics of blood through the heart and how it impacts on the overall health of a patient. A century ago, the discovery of a murmur would cause a physician to seriously investigate further, as it may have been a red flag or sign for other significant disease processes within the heart.
In the present day however, with other more accurate bedside investigative techniques in medicine, the presence or absence of a murmur has become almost meaningless. However, the lay public's perception is still along historical lines, that is, to assign a high degree of significance to heart murmurs, as if heart murmurs were a disease unto itself.
Whether it is significant or not requires a physician's detailed knowledge of that particular patient. So in essence, don't worry about the murmur, just ask your doctor "how am I doing?"