Plus if it is metal and suitably earthed then it might be a static discharge...
thinking back to my shell suit days lmao I used to get terrible shocks from my car as the nylon football shirts and tracksuits would cause a charge to build up only to discharge through me when I touched something at earths potential...
if you are comming into contact with a live potential then you must also be earthed elsewhere for a current to pass, depending on what protection you have would have tripped the house out eg... rcd, unless you have a split board with lights not on the rcd side lol.....
not a lot of people know that a live wire can be touched as long as the person touching it does not come into contact with something at a different potential ( do not try this at home !!!!!) that why birds that sit on live wires do not have an electric shock.....
can you elaborate on your problem ?
Taff