While I didn't hear what you heard last night (I was in Wal-Mart helping my friend with her groceries), I have heard high pitched noises in the past.
I'm hyper-sensitive to high pitches, and some of them produce extremely bad migraines. A Piccolo flute's A2, when played perfectly in tune, will
send me into screaming fits because it hurts so bad.
I do have an anecdote, however: About seven months ago, I was sitting in the living room with my grandfather. No electronics were turned on and it
was a warm summer night, so all the windows were open. About 8:45, just as the sun was going down over the horizon, I heard what sounded like a
really high pitched whine, sort of like when you turn on an older SD television set on after it has been off for a few hours, except, like I said, no
electronics were turned on. I was reading a book. Anyway, my grandfather didn't notice it, but I did, and my dog certainly did, because she started
whining really loudly. The migraine for me came a few seconds later and lasted roughly an hour. It was the only time that I have ever heard such a
high pitched tone outside of a hearing testing center.
My story, for what it's worth.
-TS