There's this thing with electricity called "path of least resistance." You can see a couple of examples here:
The top example shows metal probes, and the bottom shows your tweezers.
The pain you occasionaly feel is because there are nerves throughout the body in addition to the cluster around the base of each follicle. The electricity can stimulate those nerves.
A metal probe is a more reliable delivery vehicle for energy because of the follicle structure. Unlike sweat glands, follicles don't really open up that well, making it difficult to force brine or gel all the way to the root. The infundibulum tends to close unless held open by the probe.
You could solder a metal probe onto an electric tweezer device, but the probes are thin as hairs and bend easily. They often need to be replaced. Better to buy a unit that is designed for replaceable probes.
If you use a pair of tweezers and apply steady pressure to any hair for 15 seconds to two minutes, you will find they often slide out quite easily. This is especially true if they are in their last growth stages.
Do you have Asperger's Syndrome? The tone of your notes suggests you are very poorly socialized. That is sometimes a sign of undiagnosed autism. You should look into it.