Is There a Lower Decibel/Duration Threshold for More "Painful" Sounds Such as Amplifier Feedback?

Do noises such as microphone/amplifier feedback screeching cause damage at otherwise "safe" volume levels?

It got me wondering as I was in a store earlier where one of the employees would change the PA system from lower volume music to what appeared to be much louder broadcast of his voice to make announcements. And each time it would be accompanied with very shrill feedback.

This happened about every five minutes and each time people around me would complain out loud that that they should turn it off.

Even if the actual perceived decibel levels were below the desired NIOSH exposure time and decibel levels, could these types of "painful" sounds cause permanent hearing damage? Or is all volume level linear and it wouldn't matter? For example, would 95 dB of screeching feedback noise be no different than 95 dB of "clear-non-distorted music" playing when it comes to causing hearing danage?