I sometimes get questions on where to go to find Chinese herbs. In general, anywhere there's a Chinatown, there's a well-stocked Chinese herb shop, so plugging the terms "Herbs" or "Chinese Herbs" and your location into Google or other search engine can be informative. Wikipedia also has a surprisingly good list of Asian food stores (see http://en.wikipedia.org/wiki/
Asian_supermarket), where you'll find herbs and many other useful ingredients.
For San Diego in particular, here are some stores that sell Chinese herbs:
• 99 Ranch Market, 7330 Clairemont Mesa Blvd., San Diego, CA 92111, (858) 974-8899
• Nam-Bac Hang Chinese Herbs, 4623 El Cajon Blvd., San Diego, CA 92115, (619) 584-8957
• GEN MIN Acupuncture Herb Center, 2841 University Avenue, San Diego, CA 92104, (619) 297-0446
• Duong Xuan Duong, 6947 Linda Vista Rd., Suite F, San Diego CA 92111, (858) 492-9835• Phat Dong, Inc., 4619 Convoy St., Suite D., San Diego CA 92111, (858) 694-0339
• Vinh Hoa Hong, 4619 Convoy St., Suite A-1 San Diego, CA 92111, (858) 694-0339