Science anyone?

After reading Kuhn chapters 2 & 3, I have questions and I am hoping someone can shed some light. In chapter 3, he says there are 3 problems for factual scientific investigation having to do with determining which facts matter, matching facts with theory, and the articulation of the theory. He says these are problems for both the experimental and theoretical aspects of science. When he says these are 'problems' for normal science, is he saying these are challenges of normal science? I am not exactly clear what he means when he says that these 3 problems 'exhaust the literature of science' either. Is it just that there is much to be found within the literature of science dealing with these problems? On a more basic note, can anyone talk about the definition and uses of paradigm?