This may sound like a really stupid question. But what does it mean if someone is being charged with "false imprisonment"? My assumption is that they forcibly held someone against their will in some establishment and charges were pressed upon discovery... Correct me if I am wrong, please.

I'm not real sure how to take your question, as far as the defination of "false inprisonment" that would be: A detainment, or arrest of a person without a warrant, with an illegal warrant, or with a warrant illegally executed.
I assume that an inmate has told you that he/she is in prison under false imprisonment, which I would think would be his/her way of saying that they are not guilty of the crime, or that there was a glitch in the legal system as to the way that this person was sent to prison/jail.
There are really alot of different things that could mean, if you want to explainalittle more as to what the situation is, then I might be able to give you a more deffinate answer.
Best of luck in your search to find the answers !!

Actually, the inmate has not told me why he is incarcerated. I took it upon myself to find out what his record looked like. It was quite easy to find, and lengthy, to be honest. Anyhow, ONE of the earlier charges he faces on his record was false imprisonment. However, that is not the crime he is currently doing time for. So I was a little confused as to what a "false imprisonment" charge is. Does that explain it better? I have read other articles where someone is charged with that same crime, but I can't get a good explanation of what it means exactly.

Kind of sounds like kidnapping, I think.