That is a very complex and well debated question. It's why people join religions, have identity issues, are depressed. Everyone has a different answer and a different basis for the answer. You've basically just asked why are people here, what created us, how they created us, what happened to us during all the years that we have no memory of. There's not really an objective or right answer. As a christian, I believe that God put us here so that we can praise, honor and love him. That he is our father and we are his children. But there are also many, many other opinions held by other people who believe different things.