So not everything fits perfectly but this sounds really similar to the story of
I was smuggled into child slavery.
Oliver was orphaned at a young age and made to work in a workhouse
I tried to demand fairness from them, but they wanted to kill me.
One day Oliver asks for more gruel. This causes an uproar. (But I don't think anyone wanted to kill him at that point?)
They stopped, then tried to sell me to a terrible person
Mr. Bumble tries to sell him to Mr. Gamfield, a local chimney weep who is regarded to be a brutal man.
but and instead sold me to a wrestler, but he was mean and hurt me, so I ran away.
Bumble ends up selling Oliver to a undertaker (not really a wrestler, except that he lays people to rest. (maybe a pun?) The undertaker's wife and servant end up beating Oliver and he runs away the next day. EDIT: This is a pun of sorts! Oliver is sold to an Undertaker. One of the most famous wrestlers was named the Undertaker.
I found a den of thieves,
Oliver runs into the Artful Dodger who takes him back to his den of theives.
I took the blame for their actions, but a kind old man told them that I didn’t do it, and took me in.
The thieving crew tries to pickpocket a wealthy man on the street (Mr. Brownlow) but he catches Oliver. In court he tells the judge that he's pretty sure Oliver wasn't the actual thief. He takes Oliver into his home.
I got grabbed by one of the thieves, and took me back. They made me rob a place, but I got hurt, and other people took me in.
This is pretty literal. Oliver gets kidnapped by the thieves and he is forced to rob a place, gets hurt, and then is taken care of by the people he tried to rob
A really bad person killed one of my friends, but accidentally killed himself.
A senior thief (Bill Sikes) kills his wife Nancy who befriended Oliver earlier. Sikes then accidentally hangs himself running from the police.
Just a few things don't fit.
I don't know how the name James Shear relates to Oliver Twist, except that both names have a common first name and a last name that's also a verb. Also I don't think they wanted to kill Oliver when he asked for more, but I might be misremembering it...