What Causes A Stinging Sensation In The Chest Area Of A 6 Year Old?

my 6yo son randomly complains of a stinging heart - its normally around breakfast time. Not after excersise or any other physical stimulation. about once a week. he says it is not localised to a single point/spot but around his whole heart. Pls assist with what this could be / what action we should take from here. Thank You