I think there's a reason why you feel and then fear emotional pain, why to some people rejection causes emotional pain and to some not. Why to some when your being laughed causes emotional pain and to some not. It's not like pysical pain where there's really nothing behind it other than that it hurts, it will always hurt.
What if you been told your worthless all the time? But been socially accepted still always, so you wouldn't be rejected and be alone,... it wouldn't cause you pain,
What does being worthless mean to you?
That's what outgoing people are like, from their own many experiences they know they will find someone to socialize, a rejection to them is not much of a deal they move on quick to the next one
A social phobic getting rejected is painful as hell, he already feels so alone and in a moment he starts thinking no one wants him, likes him bla bla, and he won't move on
Cognitivity is a small part, iam not gona try changing, no one likes me bla bla, if this is a by product of my fearful mind. I go for the big fish, the root cause, eliminate the fear - the emotion that's driving it... and the cognitivity- believes, all will change automatically
That's why when your drunk, high, tired or whatever your always in a