getting noise when you move a wire can be triboelectric effects (the insulator becoming a capacitor when it looses contact with the wire, carrying off a charge which then causes noise as it nears or touches the insulator again, for example) which can be diagnosed by changing the wire quality.
more likely though, it is electromagnetic in origin, a twisted pair run to the switch and grounded at the 555 will reduce it, however the capacitor from pin 2 to ground is the best place to start and is probably your fix