U.S. stocks moved slightly lower on Thursday as investors anxiously awaited remarks from Federal Reserve Chair Janet Yellen on Friday. Weekly jobless claims fell 1,000 over the past week to 261,000, while analysts had expected a higher 265,000. Dollar General (DG) - Get Report shares slipped nine percent after reporting second quarter earnings of $1.08 a share, slightly below estimates. Revenue of $5.39 billion missed estimates of $5.5 billion. After drug company Mylan (MYL) - Get Report increased the price of its life-saving EpiPen by 400 percent, to over $600, the company announced it will now offer a savings card worth $300 to help cover the costs of the drug. This comes after Democratic presidential candidate Hillary Clinton criticized the price increase on Twitter Wednesday. TheStreet's Scott Gamm reports from Wall Street.