EE was working on a concrete dock which rolled causing the employee to fall. The EE worked the rest of his shift & worked the next day. On March 3, 2014 EE reported a sore back but was unsure of the exact. EE took a week of vacation to rest his back. On March 10 EE told employer that the fall was the probable cause of back injury & sought medical care on March 11, 2014.