Hello and thanks for the query
In my opinion you must go for the Echocardiography
and check for Mitral valve prolapse
(MVP). You might be suffering from that as you have heart murmur and now having that kind of symptoms like tachycardia, shortness of breath
and flutter. The line of treatment whether medication or surgery (Valve replacement
) depend on the report of echocardiography.
Do not do any stress and hard work. Do as much your body and heart allows you. Consult your cardiologist and plan your treatment accordingly.