Ok I don't really know how to describe this spot...It's only really visible on a white background it's right in the middle just one little spot thats a bit different...If you shift the phone u see it almost shimmers I guess would be the word. Sorry If I'm bad at describing
If the spot is just a black dot then it is a dead pixel, which means just that. The pixel isnt turning on. if you see a spot that looks like it is just green, blue or red then it is a stuck pixel. Both are common defects that lcd's suffer from. You could try to get it exchanged if you are under warranty and it bothers you that badly, but i doubt they will accept it unless there is significant number of them.