WASHINGTON—U.S. small business confidence fell to an 11-month low in January amid persistent worker shortages and higher prices for materials, a survey showed on Tuesday. The National Federation of Independent Business said its Small Business Optimism Index dropped 1.8 points to 97.1 last month, the lowest reading since February 2021. Scarce workers and rising labor costs remain the main areas of worry for businesses. Snarled supply chains as the global economy rebounds from the COVID-19 pandemic, fueled by massive stimulus from governments, have unleashed inflation. The pandemic, now in its third year, has also disrupted labor supply, making it difficult for goods to move from factories to consumers. There were a near-record 10.9 million job openings at the end of December. The NFIB survey showed half of the 1,504 small businesses who participated in the poll reporting raising compensation. That was the highest reading in 48 years and was up …