Recently I started a job that has me using a headset with ANC (active noise cancellation). It was OK for the first week or two but then I noticed my head hurt. My ears felt full and I had ringing in my ears that was quite loud. I have mild (self-diagnosed) tinnitus but this was beyond that by a significant amount.

I'm aware of how noise cancelling technology works it's by creating an opposing sound wave of equivalent energy to nullify the unwanted sound wave.

My theory is when I am off a call and I have the headset on my head with ANC enabled it's working to cancel the background noise. It's only needed on a call but it's obviously on all the time. These are not cheap headphones I've seen them for $300 so not cheap but I'm sure not the highest end.

I've tried taking them off, put around my neck, on my head between calls. But a few times I've fumbled them and hung up on someone or picked up before I was ready. My solution was to turn off ANC which made the sound clearer and my ears don't ring as bad as with ANC on.

My own anecdotal evidence but there is an obvious effect on my ears. I was about to go to the doctor the ringing was getting so bad.