I just started noticing a similar twitch in my left hand. It's in the meaty part of the palm below the thumb. Sometimes there are visible twitches there, but often times there seems to be a twitch I can only feel if I place a finger around that area. Pretty sure it's not my pulse as it comes and goes at difference pacing, but it is pretty persistent. I only even noticed it because that part of my palm is at a near constant ache lately, probably overusing it from working on a computer. My left thumb is very shaky lately, but I do have muscle ratcheting in most of my body ever since I've started twitching. Anytime I try to eat fries or any small food with my hands my left hand is very shaky and feels wrong. I do tend to drop things more easily now, mainly food for some reason

, but honestly, it's probably just anxiety + the muscle ratcheting which tends to be very noticeable in the hands, ankles, neck, and shoulders.
Contrary to what I said, you do have to realize that it is VERY easy to feel your pulse in pretty much any part of your hands (at least I can) and you can easily mistake it for something else, especially the people like us who stress about every little thing in our bodies.