Hi my name is a Olivia. I'm 16 years old, weigh 147 pounds, 5 feet and 10 inches tall, and I'm allergic to penicillin. Medical history isn't unusual (I'm very active and eat healthy) but I do have a family history of breast cancer, diabetes, and CAD. I've had what I thought to be a cold for a few days and I went to work today (I work in a pulmonologist clinic) and he looked at me and said I have a heart murmur. Is this serious?