" those that make what their saying true?"
^^ I have no f***ing clue what you mean by that... Anyways, I'm going to assume you're asking if it's true. I believe people who always talk about themselves think about themselves a lot, and when people think about themselves they're USUALLY thinking negative things about themselves or ways to improve themselves for other people (unless they have a high form of narcissism). I don't think it makes you selfish, I think it makes you self conscious. When I meet someone who talks about themselves I pay attention to what they say, and from what they say I try to figure out if they're self conscious or conceited. So to answer your question, yea, you're probably too self conscious.
yes. start talking and asking about them
There's an easy way to fix this. Good friends listen. Do you often change conversations to talk about yourself or involve something about you. Try asking what your friends are up to or ask a question about them. Then they will think that you care more about others.
if it's so bad that people are complaining-yeah,you have issues
If you're talking about yourself all the time, it makes you sound like a self-absorbed person.