There would have been a time when you were too young to have a concept of "I', "ego", "self-worth" or "value".
At some point very early in your life, your primary carer would have frequently neglected you, overly criticised or punished, or been erratic and unpredictable.
The small child automatically assumes that the parent or carer is right and absorbs this as a conditioned attitude of low self-esteem.
Because the emotional pain was too great you may have forgotten what happened in your childhood.
There could be other (neurological) causes, but the above is by far the most common.
It is possible to cure self-esteem issues with CBT - cognitive-behavioural training. There are plenty of good self-help books on the issue, some of which would be available in your local library.
You could also look up articles in the free online magazine, Psychology Today.
Developing a healthy self-esteem will not happen overnight. It requires closely watching your self-talk and catching and changing it.
An example...
When you make a mistake, your self-talk will probably say something like, "I'm such an idiot, I always get it wrong. I can't do anything right."
When you notice that, you can change it and say, "No, that's not true. There have been instances when I got things right (name them). I made this mistake due to (name the actual and specific cause). I can correct it and next time do it better."
You can do courses to develop new skills.
Edward de Bono is famous for his books that teach thinking. The methods of thought are broken down into simple and easily remembered concepts that can be applied to everyday life in all situations.
