Spencer Boyd’s younger self wouldn’t believe it. The NASCAR driver strapped in his car and headed to Charlotte Motor Speedway on Monday morning. It’s a destination to which he’s headed countless times since moving from St. Louis to North Carolina at age 14 to “chase the racing dream.” But until Monday, he wasn’t the one holding press conferences inside the Concord track’s infield media center, nor was he even able to attend them. Ten years ago Boyd worked as a security guard at the Coca-Cola 600. Nine years ago, he had a gig selling cars at Hendrick Chrysler Dodge. “I never would have thought …