Why do my benign pvcs are felt right under my throat like a sudden quick drop feeling?

Why not: If that's where you feel them, then that's where you feel them. You're not alone, but we're all different. Some people who have heart attacks feel pain in their jaw. It's just how it is.

PVC.: Because the main artery leading out of your heart is located there. After your PVC there is a pause during which the heart fills to capacity with blood. When it pumps that out it is felt as a thump or "drop" or something like that in the upper chest and sometimes lower throat.

Aorta, Subclavian &: Carotid arteries hydraulically stretch with each heart pump, relax/shrink in between (i.e. pulse). We quickly get used to sensations constantly/recurringly happening & consciously ignore them. However, the artery expansion after a PVC is less (less obvious) plus the subsequent is stronger (pumping both normal volume+that missed by the previous) & more obvious. This change catches your attention.