Thanks for posting on HCM,
I think you should definitely not only get a cardiac ultrasound
and/or EKG done, you should also get a cardiologist's opinion. It would have been nice, if you were able to mention what condition was diagnosed 12 years ago when the echo was done. If the heart murmur
actually had a cause, it may have been a congenital problem given your age or a possible valvular/endocardial infection such as endocarditis
(fever would have been normally been part of the presenting symptoms at that time). If your early heart murmur was a benign paediatric heart murmur (functional). Functional murmurs are an important consideration in the precordial examination
of an infant or child.
Now that you are older, it is paramount for you to consult a cardiologist
Hope this helps