That inner monologues - thoughts of a character emotions etc are really death to a play Is this true? Is it just because I'm a foolish beginner that I have been using this "tool?"
Not sure what you mean but I rarely see inner monologue transferred to the screenplay when a book becomes a movie. They generally use something else to show you the actor's reactions/thoughts. Less commonly inner thoughts are done as a narration over the scene like Kevin Spacey's character does on "House of Cards".
Are you using it in a play or in a short story or novel? The two are quite different, so what applies to one is not necessarily going to apply to another.
I have no experience writing plays, but I have some amateur acting experience. If it's a 10 minute monologue I don't see that there should be a problem. A monologue is just one person anyways right, so what's the problem? Monologues often express inner thoughts. Is it a play or a screen play? I would advise you to be careful writing a monologue that is more than 2-3 minutes. You have to keep it exciting. What is the monologue about? It sometimes depends on the actor as well. Not all actors can handle a monologue of more than 4 minutes (if I remember correctly, it's four years since I played). This will often result in the director edits parts of it out. This way what you think is the most important part of that monologue might be left out, but it's not many ways for the writer to fix this. So maybe it's better breaking it down, so that the most important thought get expressed, but at the same time you don't loose your audience's interest or your intentions with the story? Excuse my English. I hope this was a little helpful.
I would regard a monologue as distinct from a play. A monologue would be fine to include a character's inner monologue but it has to be handed carefully so it doesn't feel like reflection, narrative or exposition just thrown in to keep things moving. I read very few monologues but one that would be worth referencing is Camus' The Fall as it is a monologue based novel and therefore much longer than those you typically find on stage.
A ten minute monologue might be a bit intense if it's part of a larger play - but it's not at all bad to "break the fourth wall" and have the character start musing to the audience about the action on stage. As mentioned, the Kevin Spacey character in House of Cards does this often. So, by the way, do a lot of Shakespearean characters. In "Midsummer Night's Dream", Puck often lets the audience know his thoughts - and a good portion of "Much Ado About Nothing" is Beatrice and Benedick talking to the audience about whether or how they should pursue each other's affections (In that case it's absolutely maddening because - since you're in both characters' heads - you as an audience member know that both of them are falling for each other and then want to strangle them for not getting it). I don't know your play, but my advice would be to break up and/or condense your monologue so that it's not one long boring scene. Have action going along with it maybe and then freeze it so that character can address the audience or something like that (again, House of Cards). Look for examples of writing where characters talk to the audience a lot and work from those examples.
Inner monologues are usually "telling" as opposed to "showing." Audiences usually react emotionally stronger when inner monologue is changed to a dramatic action.
That's true but when the character freezes to think at a dramatic moment it can actually heighten tension if done correctly.
