My son had an ekg today and was told he has incomplete right bundle branch block, he is only 17 should i be concerned ?

Probably ok: The pattern that triggers the automatic diagnosis of IRBBB in an ECG machine is an rsr' in lead v1, (pronounced: "r s r-prime in v-1"). This pattern is not uncommon and may represent a normal variant, especially in young people and children. If other symptoms occur or conditions are suspected, such as an asd, the ECG and patient will need to be evaluated by a cardiologist.