very easy fix. EVERYONE IS DEFFIERENT. You need to realize that your a natually quite/shy person. And that its ok to be this way. you probably here all the time stop comparing yourself with others. Well stop comparing yourself with yourself lol. Start accepting who you are.
step 1. when a sittuation occurs and you feel like you need to talk or step out and be more open. DONT

give it a try for a long time.