The best fresh pasta in San Diego is at Assenti's Pasta in Little Italy. It is run by a pair of brothers, and they supply many of the finer restaurants in San Diego. They also make fabulous homemade sauces, biscotti, caponatina, meatballs, and sausage.
2044 India Street
San Diego, CA 92101
I don't know where you are in California but if you are close to San Diego the best fresh pasta is available at Russo's Pasta in Encinitas:
Russo's Pasta Shop
270 N. El Camino Real, #1
Encinitas, CA 92024
I think they opened now also a restaurant in Hillcrest where the Talus Cafe was before.