if a reaction can occur in the presence or absence of stimulus, how in the heck are you saying you "have" it. it could be a reaction to a caffeine stimulant heavy diet for all anyone knows.
this seems to be in the same realm as micro-aggressions for how provable they are to be a real problem
Personally I didn't experience it in the "absence" of the stimulus, so I cannot comment on that part.
I only wanted to point that absence of some irritation or uncomfortable feeling in presence of the stimulus for one person is not enough for one to label such sinister and delicate matters as "not real" or "non-existent".
It's just the concept that unfamiliar ambient noises can become very grating to some people. Someone used to a particular fan might struggle with the sound of a different one. Someone used to the sound of a CRT TV might ignore it, while other people can't. Likewise, someone not used to silence can be uncomfortable with the lack of stimulus. It's a common aspect of sensory processing abnormalities, such as autism. It's well documented and entirely reasonable. Just because it's not a standalone disorder doesn't make it fake.
Personally I can't stand people who are eating stuff or chewing gum while they are on the phone with me. Same with noisy eating in a silent place. I sometimes silently leave the place if I can, or warn the eater as politely as I can, if he/she's my friend.
Heck, if I'm extremely tired or weary I can not even stand myself sometimes.