Home Improvement Questions? Ask a Handyman for Answers
The only thing that pops into my mind on this. Do you have an attic fan of any kind? Suggestion, you say it sounds like it is coming from the kitchen lights. Is there any way you can get into the attic to see what is going on up there in that area?
I am not sure but did you say you turned off all the power from the main and you still get the noise or just one circuit at a time? You should turn the main breaker off and see if the buzzing stops. If you turn off the main and you are still getting noise you can be pretty confident that it's not the electricity.
Did you check for carpenter bees? They make a noise such as you describe. They nest between walls normally but in your case (if you have them) they may be in your attic or in the space between your ceiling and attic floor (if there is one). I have seen them under the insulation. If you can get into the attic check for hornets or bees. Be carefull when you investigate as hornets will chase you and sting. Carpenter bees (look like fat bumble bees) can be aggressive but will turn away rather than attack. One long shot: Do you live under high tension power lines? They buzz too.
Hope I helped :)
Since we all know it's not the electrical nor your lights. If the noise is a bother (which I'm sure it is) one of 2 choices I would guess. 1) Call pest control to rule out any type of bugs.. 2) Could even call a home inspector in and let them check it all out. Not sure where you live. But here in FL they usually run around 100.00
Good luck in your venture.