I'm not sure as I haven't got enough information about it yet. But usually in such stories, there would be characters who are central to the hustle. It could be a person who starts the whole journey of this 'pain hustle' and the people around them who support or oppose what they are doing.
Since we don't have a lot of details about 'Pain Hustlers' based on true story, it's difficult to say exactly who the main characters are. However, if it's about a business - related hustle, there might be a protagonist who is trying to make it big in a cut - throat industry. There could also be a mentor - like figure, or perhaps rivals who are also vying for the same opportunities. And there would likely be family or friends of the main character who are affected by their actions and decisions in this 'pain hustle' journey.