Dr. Jason Wersland, a chiropractor, invented the Theragun while trying to manage his own pain after a motorcycle accident.TherabodyThis as-told-to essay is based on a conversation with Dr. Jason Wersland, the founder and Chief Wellness Officer of Therabody, who lives in Los Angeles. This story has been edited for length and clarity.On October 17, 2007, I was on the freeway, splitting traffic on my motorcycle. A car came out of nowhere, and I T-b…