Noise around outlet, help

I've decided to get an electrician to come in and take a look at all the outlets I've switched in the past and inspect the whole house for any lose wires. Better safe than sorry with this stuff, thanks all.

Hello, thanks Albert and Glen.
I've worked on it this morning. The Hubbell is from World Power, has side terminal screws, copper wiring, and was installed by me.
I've cut off about 2 inches on all the hot, neutral, and ground and reconnected the Hubbell. It seems like the wires were too long and may have rubbed against one another when I pushed the outlet back in the first time. The hot wires weren't touching anything, but it looks like the ground could've been rubbing against the uncovered part of the neutral (connecting terminal).
Prior to reconnecting the Hubbell, I've connected the Nite to an extension cord to another outlet and it wasn't making any noise. I've had everything reconnected for about an hour now, and there's no noise so far. My guess is that the ground, when pushed in the first time, formed a semi-circular shape that extends up, parts of it touching the small exposed area of the neutral wire or the terminal itself.
I will keep an eye on it today to make sure nothing else happens. I've done this before with no problems, but I have no technical/electrical background. Thank you for your suggestions, and please comment if my guess doesn't seem logical.