"The man had a flashback of his past after watching the movie"
Good writers don't usually use flashback at all, to be honest.
I think flashback
Flashback
I just had a flashback on the day i fell into 100 bucks or that flashback was bad or haha ha i just had a flashback
There is no prefix.
This is one form of a "flashback."
The flashback was about when my dog died.
atari flashback
Flashback
flashback
It really depends on the length of your flashback (e.g. a paragraph vs a few pages) and the tense used in the rest of your story. However, it's common for the past tense to be used.