It has been called a lot of things by many different trainers, your dysfunctional inner voice, your drunken monkey, your negative self talk re generator. It doesn't matter what you call it we all have one.
Our personal experiences, circle on influential friends and our family of origin all have a way of programming the messages but we all have messages that do not serve us. 
The trick is two fold:


1. Don't argue with your inner voice. If you have an above average intelligence your subconscious voice is better at forming a convincing argument than your conscious voice. Having a battle of the wits with your inner voice is like taking a knife to a gun fight, foolish. Also these battles can last for days or weeks or more. While you are battling your are out of momentum and ostracizing yourself from your team. Stop arguing and get back into action. Take inspired action whether your drunken monkey is screaming or not.

2. The presence of a self sabotaging, self deprecating or idiotic self talking inner voice is not proof that you cannot succeed in The Evolved Economy. You are not flawed. You are normal. I coach people at every level of personal success and they all have one thing in common, self talk that does not serve them. More cash does not silent the monkey, in fact it gives him a mega phone! 
You are gifted and talent, inspired and exquisite and the person who is trying to convince you otherwise is either in competition with you or has their hand in your pocket. 
Surround yourself with people who recognize your greatness and are willing to remind you when you forget. 
WE ALL FORGET FROM TIME TO TIME!