Non scientific explanation would be that kind of feelings are part of being human. Scientific explanation would be related to chemicals in brain either produced more in some instance or less in some instances. And these hormones have some sensory and motor actions . Sensory could be feeling excess of emotion or opposite of that feeling numb. The increased emotions may be perceived as some uneasiness /heaviness in chest. If the emotions become excess then other physiological things happen side by side for ex : increased blood pressure if other risk factors present then person might end up having heart attack. Hope it gives you something to think about.