The Throat chakra is about self-expression and talking. When it is open, you have no problems expressing yourself, and you might be doing so as an artist.
When this chakra is under-active, you tend not to speak much, and you probably are introverted and shy. Not speaking the truth may block this chakra.
If this chakra is over-active, you tend to speak too much, usually to domineer and keep people at a distance. You're a bad listener if this is the case.