Insecurities usually have a root cause. You find the source by its root, and deal with it there. Only you know the question to this. A psychologist might help, but you are the one who controls your own life.

about talking to a girl about your insecurities. I dont really agree with that fully. There has to be a balance. I think it turns girls off when a guy throws all their insecurities on them. Its cool to show girls you are human once in awhile and when you get close, you can share things, but dont dump it on her. They dont like it. In fact they probably wont like you for it. Thats why girls are attracted to assholes. They like that confident laid back personality.