SOLVED. Science fiction. Young man is found guilty of a crime he did not commit, and forced to wear a ring which controls behaviour. Read about 1990. Spoiler ahead. [s]

[James]

Although he proves himself innocent in the end refuses to have the surgically implanted ring removed

[Kris]

James, around what year did you read this book? A range of years is fine.

Is this book for teens or adults?

What's the crime he's accused of committing?

[James]

Not sure probably 30 years or more? Again could be young adult.
Sorry long time ago!!

[Andy]

Possibly "The Ring" by Piers Anthony https://www.goodreads.com/book/show/2...

[Sue]

That was my first thought. Does the ring cause physical pain if the wearer does/thinks anything bad?

[James]

Yes that is the book, many thanks.

[Andy]

Glad to help (I didn't notice that you had marked this one solved until tonight).