Problem in microphone circuit
You might be picking up environmental noise; basically all aspects of your implementation make that likely:

Breadboard is exceptionally great at coupling in signals you don't want
So are long, loops of wire
You're using an amplifier IC with known-to-be-bad output noise, without appropriate filtering
Your schematic has no decoupling capacitor on VCC of the amplifier

additionally,

you're using an audio power amp as a preamplifier - that's a bad choice, and might/will lead to distortion. An opamp circuite (eg. the simple inverting or non-inverting amplifier) with appropriate dampening of high frequencies (e.g. through a capacitor in the negative feedback path) would be a better choice, and on top of that, use much less power. Even used as a small power amplfier, the LM386 is really the worst commercially available audio amplifier.