It's the first in a series of fantasy books.
The boy has a ring that he doesn't know is magic. He gets into a fight one day with another boy and ends up accidentally killing him with the power of the ring. He then gets transported by the ring somewhere else and eventually ends up learning that he is a chaos god and his power was trapped in the amber stone of the ring.
There is a love interest at some point as well maybe? She might end up dying and getting resurrected, or something like that.
There's a lot more than goes on in it but I can't remember!
Book is likely to be from the 80s or early 90s.