I have heard that there is a task for everyone to fulfill before they enter shamayim, but what happens if you had a chance to fulfill your task in life and you missed it? do you get a different task? do you still have another opportunity to go and fulfill your mission Hashem put you on earth for?!?
Astounding! Read the first few chapters in Shaar HaGilgulim from the Arizal. One must fulfill all the 613 mitzvos b'machshava b'dibbur uv'maaseh. That means to fufill all of them in deed through speech and thought, through limud hatorah and the kavanos according to the Kabbalah. If one does not do it all in one lifetime, he gets at least three more chances.
The Mitzva of Pesach Sheni indicates that G-D gives second chances. We must not miss that chance in this life or else we must repeat by living in another body in another time. For details, the sefer has several current translations, one of which is out of print.
Can you please provide a Torah source indicating that everyone has a particular task in life?
As far as I can tell the Torah itself makes no indication that we have individual tasks/mission in life.
We must all try and develop ourselves through living a life based in Torah and reason. We each use our given strengths and weaknesses, but primarily according to ones knowledge and relationship to God will determine ones portion in the world to come.
Thank you for considering this perspective.