Paine speaks of this in chapter 7 "Examination of the Old Testament". Paine claims that the use of these words in their original intention "strips it of all religious meaning". This is the first I have ever read about any contention over the meaning of a prophet and I would appreciate any information on how this statement is currently viewed by historians. Thank you.
Poetry in Hebrew is שירה, shirah. Prophecy is נבוּאה, nevuah. While almost all of the books of the Hebrew Bible contain poetry (including all the prophets, with the exception of Haggai and Malachi), the two ideas are unrelated. Prophecy could be expressed in poems as well as other ways, and poetry/song could just as easily be secular.
I can't answer your question about how the word changed in Christian tradition, but I can definitely tell you he wasn't getting it from the Hebrew.