iphone SE frame Vibrate during Charging!!

What you feel is leakage current from the pair of capacitors shunting the high frequencies at the charger’s prongs to “ground”.

Since most chargers are not grounded (they have only two prongs, not three) this ground is connected to the output wire and floats at about half the mains voltage.

You can feel the same “vibration” with other ungrounded electrical equipment like those radios or TV sets with a thin cable and two pronged plug.

However, the capacitors are very low capacity so the leakage current is very low, barely noticeable only when you concentrate it in a small area of skin. When you rest your entire hand the current is distributed across a larger area and you can’t feel it anymore.

AC starts being dangerous at about 20–25mA while typical leakage current is under 0.1mA. Unless one capacitor short-circuits (but they are typically rated 3000V so chances are low) you are in no danger.

If you want to be very safe find a high-quality charger with complete insulation or one with a ground contact (and insert it in a grounded socket).