I wanted to re-read this but can't remember the title. I read it 10-15 years ago but don't know if it was new at that time. The plot centered on a human who had learned an alien technology that allowed him to build planets and be immortal. Another planet creator tries to kill him.
(edit) I don't remember the cover or author. It was at least novella length but I think it was a full stand alone novel. More specifics on plot as follows (IIRC):
The story begins on a planet he created for himself as a luxury planet responsive to his every whim. After recognizing an attempt on his life, he discharges a paid female companion and takes off in a private spaceship.
I recall that he was specifically human because it was a big deal that he had learned the technology as few or no other humans could master it. Mastering the ability required attuning oneself to what the aliens considered gods but there was debate as to their actual makeup (i.e. sentient "gods", accessing universal archetypes, etc).
He travels to talk to either his teacher or else some other elder masters to figure out who is out to get him. He then travels to a planet made by his enemy which turns out to be a planet sized personal trap. If I remember correctly his enemy was attuned to either a lightning or storm type god or archetype.
It isn't the Farmer novel noted below that that was a very good suspicion based on the limited stuff I originally posted.