El Segundo-based MacMall, the online and catalog retailer of Apple computers and software, is expanding its retail stores, saying that it has opened up a new retail store in Chicago. The catalog retailer--which is a subsidiary of PC Mall, Inc.--said the store is its first in the Chicago area. The firm also runs three stores in Southern California. PC Mall did not say if the new store is a start of a national expansion of its retail efforts, or if it has further retail plans. The company has primarily been known as an online and catalog computer retailer.