There's a Greek belief about choosing your parents, your life, and the problems in the world. As mentioned in this video. I'm trying to find the full story/myth. Where can I look?
Wikipedia gives a good synopsis, but here is an excerpt from the source material on Perseus, with some added links to provide context on their next life choices:
He said it was a strange, pitiful, and ridiculous spectacle, as the choice was determined for the most part by the habits of their former lives. He saw the soul that had been Orpheus’, he said, selecting the life of a swan, because from hatred of the tribe of women, owing to his death at their hands, it was unwilling to be conceived and born of a woman. He saw the soul of Thamyras choosing the life of a nightingale; and he saw a swan changing to the choice of the life of man, and similarly other musical animals.
The soul that drew the twentieth lot chose the life of a lion; it was the soul of Ajax, the son of Telamon, which, because it remembered the adjudication of the arms of Achilles, was unwilling to become a man. The next, the soul of Agamemnon, likewise from hatred of the human race because of its sufferings, substituted the life of an eagle. Drawing one of the middle lots the soul of Atalanta caught sight of the great honors attached to an athlete's life and could not pass them by but snatched at them.
After her, he said, he saw the soul of Epeius, the son of Panopeus, entering into the nature of an arts and crafts woman. Far off in the rear he saw the soul of the buffoon Thersites clothing itself in the body of an ape.
And it fell out that the soul of Odysseus drew the last lot of all and came to make its choice, and, from memory of its former toils having flung away ambition, went about for a long time in quest of the life of an ordinary citizen who minded his own business...
SOURCE: Plato The Republic 10.620a-c
After making the choices and having them affirmed by the Fates, the soul must forget their former life before being reborn:
And after it had passed through that, when the others also had passed, they all journeyed to the Plain of Oblivion, through a terrible and stifling heat, for it was bare of trees and all plants, and there they camped at eventide by the River of Forgetfulness, whose waters no vessel can contain. They were all required to drink a measure of the water, and those who were not saved by their good sense drank more than the measure, and each one as he drank forgot all things.
SOURCE: Plato The Republic 10.621a