Another massive injection of federal cash could ignite the economy like never before. It also could drive up inflation and burst market bubbles, creating new headaches in an otherwise positive outlook.A woman walks past a "Now Hiring" sign displayed at a CD One Price Cleaners in Schaumburg, Ill., on Feb. 6, 2021. | Nam Y. Huh/AP PhotoCongress on Wednesday approved the largest injection of federal cash into a growing economy in U.S. history. The nearly $2 trillion stimulus package headed to President Joe Biden’s desk comes after lawmakers approved nearly $4 trillion last year as the economy...…Another massive injection of federal cash could ignite the economy like never before. It also could drive up inflation and burst market bubbles, creating new headaches in an otherwise positive outlook.A woman walks past a "Now Hiring" sign displayed at a CD One Price Cleaners in Schaumburg, Ill., on Feb. 6, 2021. | Nam Y. Huh/AP PhotoCongress on Wednesday approved the largest injection of federal cash into a growing economy in U.S. history. The nearly $2 trillion stimulus package headed to President Joe Biden’s desk comes after lawmakers approved nearly $4 trillion last year as the economy...WW…