I want to know whose mistake or fault it is that I have to suffer in this world which I didn't choose or decide to live? Is it my parent's fault or their parent's parent's fault?
No, your existence in this world is not your fault.
Your soul chose who can be a mother even much before you were formed in her womb.
It is the result of various factors and events, including biological processes, that are beyond your control which makes you feel negative.
You have the power to shape your life and make choices about how you live it, but the mere fact of your existence is not something you are responsible for.
By no means. As the previous post says "it is the result of various factors and events, including biological processes, that are beyond your control which makes you feel negative."
More to the point, you did not choose the family where you were borne, nor did you choose the physical, psychological and social milieu where you were born and are growing up. However, after the two just mentioned events, you are also responsible for your education and development.