Insurance companies are not medical doctors...though they pretend they know everything. Two years is a common interval for them to complain (that and as $10,000) Make sure your chiro knows that they are rattling your cage again. Be firm with them, in writing. Keep copies of everything, organized as best you can. If you don't have an attorney, get one...but don't plan on settling medical until you find you can work without pain. Trust me, I know these things.