Stocks spent much of the day wavering between tiny gains and losses, but the S&P 500 eked out its third record close in three days. On Tuesday, the index ended above 2,000 for the first time. ‘Having achieved this 2,000 level, the market is simply taking a pause,’ said David Lebovitz, at JPMorgan Chase. Early Wednesday, investors focused on earnings. Express Inc. had better-than-expected results; the stock surged 12.8%. At 10 a.m., the Congressional Budget Office projected the economy will grow 1.5% this year — more pessimistic than the White House’s 2.6% forecast. Stocks fell, then recovered, only to waver through much of the day.