Sometimes a high BP is just a reaction to someone measuring your BP. One side effect of a high BP is that you hear the thumping sound of your blood pulsing.

I personally have my heart rate and blood pressure explode whenever anyone tries to measure them. So I was referred to a cardiologist who did some basic checks like an echo, found nothing wrong and wired me up to a device that measures BP continuously for 24h. My BP was perfectly normal.