a) yes, there are people who likes you but you don't know because you don't get involved with people.
b) People like strangers are neutral at you, but people that is in your community( job, school, family) likes you.
c) If there are people who hates you, they don't care about you. So, don't care about them; If they bothering you: just tell them: you can say anything about me What you say doesn't affect me because you are not important to me and I don't care about you; then turn around and walk away
2) you're right social phobia is fear of some social situations that are going to trigger you anxiety. you have to find which situations triggers you anxiety and work on that.
3) Rejection is not real when you are social phobic because no one really knows you.
The trick is to improve your social skills. how? talk to people short conversations. Do this whenever you feel comfortable to do it. or just say hi or bye to someone.