Are you referring to a humming sound?
Singlecoil pickups (those usually found on Stratocasters) are susceptible to what is called "60-cycle hum" as well as feedback (noise) so I'd say humming is quite normal. Especially if you go too close to your amplifier.
You won't get the humming (or at least it is much reduced) by switching your pickup selector switch to either the 2nd or 4th position because if I'm not wrong, those two positions have two pickups running together, thus cancelling the hum.
Hope this helps!
