There can be multiple causes of heart murmur
Even they can be innocent murmurs
You said he had viral infection before that.. Did he had sore throat?
Viral infections and a Streptococcal infections can damage heart valves producing murmur.
2D- ECHO can confirm if he has damaged heart valves.
You said his pulse is abnormal.
What abnormality is there we need to know. Is it irregular?
Your doctor must have seen for conditions i am talking about.
Please send us the reports.
Get his Echocardiography
Dr Anshul, M.D.