Ill be in San Diego for a few days at the end of May, can someone please suggest a few must see breweries, and a few good beer stores?
you did not give enough info for any useful advice. I agree with doing research, searching this forum and here is a map to get you started.
OP, your best bets are probably Karl Strauss, On the Tracks, Rock Bottom La Jolla, and Poor House brewpub. Check nano's map for their location.
OP, just a bit of advice. I've always had the most thoughtful trip suggestion responses when I've provided specifics such as the hotel i'm staying at, dates, length of time, as well as a list of places that I'm interested in visiting (from prior research). That way, people can provide feedback on said research as well as alerting me to things I may have missed or that only locals are privy to. This has worked on every forum I've been on and I have yet to experience snark and hostility from those who are tired of having to answer the same questions week in, week out (sometimes everyday even).