Maybe the darn thing was just too tight? The only other thing I can think of is you have a weird sensitivity to sound wavelengths. The way ANR works (in my oh-so-basic physics understanding) is it analyzes repetitive sounds such as engine droning, wind, prop noise and "cancels" it. If two sound wavelengths are opposite (one peaks while the other valleys), it's called destructive interference. They cancel each other out, and it can't be heard. This is what the ANR in the headset does. That's why you can still hear music clearly or a loud bang from your engine (they're not repetitive). If your ears are sensetive to the change in wavelengths, frequencies, or whatever, I could certainly see you getting headaches from that.