Everyone has offered you good advice. Just try to remember that running is an acquired taste, so it takes a little getting used to. The initial general discomfort passes quickly.
I completely forgot to mention the part about getting a good fit on your shoes (I should know better; I worked at a running store for a few years during grad school). That will make all the difference in the world. Make sure you try on a few brands and styles. Remember that the best running shoe made is the one that is most comfortable to you.