If this happens on all the parts of your computer including the monitor, you probably have some problems with your Power outlet, or your power plug, because it is normal some times to get a little tingle from the PC's case while touching it but it's not normal to get that tingle all the time.

If this tingle is felt all the time on the monitor too then it is very clear you need to go to the nearest PC service, because you may have some problems with your power outlet or you may have some problems with the pc's power source.

A power outlet definition: domestic AC power plugs and sockets allow a connection between the mains electricity (household, usually single-phase, AC electrical power) and the appliances commonly used in homes.