Some philosophers call natural disasters and bad experiences evil.
I, however, would suggest that the only evil in the world is deliberate, conscious evil done by people who have rejected the good (God).
The rest is done by humans of their own free will.
Natural disasters are accidents caused by the actions of natural forces in the earth. These natural forces act autonomously - i.e. without the conscious intervention of God.
As for bad experiences, the chances are that if you treat people well they will treat you well in return, and if you treat people badly they will treat you badly in return.
This, however, is not a Law.
People have free will and act according to their will.
People are free to return ill for your good or good for your ill.
God is not responsible for what happens to you in the world.
Other members of the human family are responsible for their own actions towards you.
Our task is to be grateful and forgive.