Hi, welcome for your query
The function of tonsils that are situated on either side of your throat walls above and posterior to the tongue is to trap and kill the infective agents and thereby protecting the lower air and food passages.
But sometimes they cannot clear the infective agents and themselves become the seat of infection called "tonsillitis".
The thriving infection - usually bacteria or its products can enter the bloodstream and causes further complications.
In response to infection, our body produces some products that increases the number of fighting white blood cells. Normal count is 4000 to 11000, and in your case it is increased to 22000 suggesting there is some infection in your body.
With treatment of infection with antibiotics the count will become normal.
The Heart murmur
found and the symptoms mentioned by you, can be of some concern. The tonsillitis can give rise to heart complications like Rheumatic Fever/ Rheumatic Heart Disease
and Subacute Bacterial Endocarditis
which needs a proper evaluation by a cardiologist.
It can also be because of Increased Heart rate
( Tachycadia) that will be associated with acute infection, like your increased WBC count
, that will settle down once you ward of your infection with proper antibiotics.
You should definitely visit your doctor for proper treatment.