What did the word redneck really come from?

There is no definitive answer to this. It is thought that is was applied to describe those poor white workers who labored in the fields in Georgia and other southern states. It is also attributed to miners who were members of a union and that would wear red scarves around their necks so they could easily distinguish one another. Since they would not be in a position to get red necks from working underground the red scarf may symbolize the plight of the poor white worker underground and when emerging from a day in the mines looked like black slaves. Therefore the former had given rise to the latter. Red neck is now attributed to a non-conformist, an independently minded individual that is not swayed by public opinion or accepted values. Originally an observational thing and somewhat derogatory like the term wetback to describe a lazy immigrant Mexican worker. Which implied that he had been leaning against a wall asleep and that was the cause of his shirt back being wet otherwise the sun would have dried the shirt.