Question: When we born in Pure Land, do we come back to to the world to help others?
Response: The first of the Four Great Vows is "Sentient beings are innumerable, I vow to help them all." We go to the Pure Land not just to end our own suffering, but to help all beings end theirs.
This vow becomes the underlying inspiration for our cultivation, practice, and learning.
In the Pure Land, we learn all the different methods to be able to skillfully and wisely help others. We are thus able to come back to this world, and to others, to help those we have affinities with. We do so through the strength of our vows, not the pull of our karma. Our true being remains in the Pure Land when we come back so we are never separated from the Pure Land and run no risk of again being lost in samsara.
This way we always continue to progress towards Buddhahood and help others progress as well.