I know exactly where it started. In high school when I finally had a group project with 3 of my long-time friends and ended up being the only one who did their part after we agreed how to split up the presentation. It embarassed me so much, I froze up and could not speak despite trying which freaked me out and I had to go to the nurse. Ever since, if I am too emotionally overwhelmed, I become physically unable to speak.

I used to be pretty outgoing before that.