If you feel you have schizoid personality disorder, you should go see a professional. Especially considering that if you have schizoid personality disorder, you have a personality disorder but no desire to see professional help. When you feel that you ought to go but are hesitant, surely you should go.

That said though, a personality disorder is a personality disorder. The schizoid/avoidant/narcissistic/borderline/paranoid are just personality traits one may or may not have, regardless of mental health. Only when they dominate your personality and disrupt your life, it is a personality disorder.

My experience is different, I guess. At some point all my social interactions were either with you parents or with random people on the internet, often in video games or some discussion board (and that usually results in arguing/insulting).

Then I discovered true people, on the surface, are actually nice and engaging. But not more than that. I cannot distinguish politeness from displayng interest and me shutting it down, (maybe).