February looked to be a chilly month for retailers as higher payroll taxes and gas prices likely caused shoppers to tighten their purse strings. As of Wednesday, analysts were expecting February same-store sales, to be released Thursday, to rise 3.3% vs. a year ago, says Ken Perkins, president of Retail Metrics. The estimates exclude drugstores. "By all indications February was a pretty choppy month," said Perkins. "Retailers were up against a lot