What is monologue? what is the difference between monologue and thinking to yourself and give the examples of monologue.

a long speech by one actor in a play or movie, or as part of a theatrical or broadcast program.
synonyms:soliloquy, speech, address, lecture, sermon, homily; formaloration

examples
"he quickly launches into another manic monologue"
a long and typically tedious speech by one person during a conversation.
"Fred carried on with his monologue as if I hadn't spoken"

You're speaking a monolouge, when you are thinking to yourself, normally not saying it unless to let an audience know. A monolouge can include what you are thinking or giving a speech.