Necrosis in pericardium has several causes.
It can be caused by viral infection and gets better on its own after some time.
Cardiac trauma also can cause some amount of necrosis. Constant rubbing of myocardium with sternum because of low pericardium fluid may also result pericardium necrosis.
Due to injury of
thoracic duct, there may be lymphatic effusions in pericardium which may cause thickening of pericardium and thus pain
But it is very rare. Also blood effusions because of trauma can cause the same.
Another rare cause is amebic
pericarditis because of infestation by ameoba.
Cardiac neoplasm are another probable reason for chest pain.
calcific deposits in pericardium can cause chest pain.
Cholesterol deposits in pericardium induced by
Hypothyroidism can be another reason.
The most common and innocent cause of chest pain is obstructed gas in the alimentary canal.
There are other factors not applicable like
cardiac surgery,
renal disease etc.
Getting your son tested is the best way to find out, if the chest pain persist.