I was involved in a 4 car accident. I was the first car rearended. Should I hire a personal injury lawyer?

I was at a stop light on the 14th street offramp off the 91fwy in riverside CA. The vehicle that ran into me did not brake at all. He claims he fell asleep at the wheel and that this is the second time in 3 months. I went to the emergency room the next day with neck, chest and back pain. My main concern is that I already have a work comp lawsuit that includes the neck. I believe this accident may have aggravated it but don't want to cause issues with the work comp claim.