I hear a High Pitched Ringing? I hear a High Pitched Ringing Sound From my Attic. It starts...

I hear a High Pitched Ringing Sound From my Attic. It starts getting louder.. then decrease in nouns and goes sour. Dont know what it could be.. Possibly Electricity? or Because of Coldness?? I have no model.. But I would like to know some possibilities, because it may be terrifying.
How do I verbs a chimney near a...
Answers:    yes, you will have to step take a closer look. nought else for it...
Air conditioner section!?
what do you have contained by your attic furnace hot water heating system go up and check it out sit up nearby till you here it