I would have read this in the early 90s. I remember a kid was basically a slave to an alien living in a futuristic city on a planet with higher than earth gravity. I think maybe he had to wear some sort of breathing apprentice too. I think this book was part of a series. I know I don't remember a lot about the book. But I do remember it was right around the time I really started to enjoy reading. So I would love to track this down if possible.


Any ideas?

The Tripods?
if so here is the link
https://forum.mobilism.org/viewtopic.php?f=1295&t=841431&hilit=tripods