As superchoc said, no symptoms of pregnancy will occure before implantation. It isn't until implantation that your body begins to produce the pregnancy hormone HCG. HCG is responsible for the pregnancy symptoms.
any pregnancy related symptoms can not start until the egg is implanted at least a few days, which is why you can not test for pregnancy too early. sore breasts are more than likely a hormonal thing but wait it out and see, try testing in a week or so. good luck