For many of you, you might know that it's due to a loud noise or loud noises that caused it. For some, ours came out of nowhere for no reason at all. I'll start on mine: I think mine is due to a virus that is affecting my liver. I'll know for sure as I am treated and if it diminishes or goes away when the virus is undetectable, then it's definitely that. Might take 6 months or even 2 years.