Screeching and Coughing!

Ga
My son discovered how to just randomly start screeching and does it 24/7 I swear to god. Then he does this thing that almost sounds like he's choking? The first time he did it, it terrified me but I think it's just a new noise he learned how to do so he just keeps doing it?! 
It's just so, I feel horrible saying it, but so annoying and I can't wait until he finds something else to do!