In Reply to: Get it off my chest posted by Jen B on November 25, 2008 at 14:13:
: Does anyone know the origin of "Get it off my chest" or similar?
The Oxford English Dictionary defines the phrase, "get something off one's chest," as meaning "to relieve one's mind by making a statement or confession," and cites as its earliest example "1902 Daily Chron. 27 Sept. 3/2 The desire is either to deliver a message to the world or to express the individual personality--to 'get it off your chest' is the horrid, vulgar phrase."
Although one need not concur in the characterization as a "horrid, vulgar phrase," it's true that it can refer either to something you feel you need to say because it needs saying, or to something you need to say because it has been "weighing on your conscience."
From the eighteenth century on, writers and especially poets have talked about duties, delays, other negative things as "weighing" upon people or their spirits. The case of the weight upon the chest is interesting, as references to body parts often have a physiological basis. Having "a lump in your throat" is an example on one which has been elucidated as a feeling which results from s specific chemical change in the body. Having something weighing on the chest almost invariably accompanies nightmares (although the converse is not necessarily true--nightmares do not always accur if something weighs on your chest).