WASHINGTON—The number of Americans filing new claims for unemployment benefits dropped to a 14-month low last week as companies held onto their workers amid a growing labor shortage that helped to curb employment growth in April. The scramble for workers comes as the reopening economy is experiencing a boom in demand, resulting in widespread shortages of inputs at factories and fanning inflation. Producer prices increased more than expected in April, leading to the biggest annual gain since 2010, other data showed on Thursday. The worker shortage is despite nearly 10 million Americans being officially unemployed, a disconnect that economists expect will resolve in the coming months as enhanced unemployment benefits expire, allowing some workers to return to the labor market. “With demand for workers high and layoffs relatively low, we should see strong hiring in the months to come, as barriers to employment, such as lack of childcare, lessen,” said …