Massage therapy has been proven in numerous studies (*a couple of which are referenced below) to reduce both non-specific neck pain and neck pain from injuries and car accidents. Additionally, massage therapy combined with stretching, strenghtening exercises, and self-massage can reduce the number of tension headaches a person experiences and perhaps even prevent them altogether.
To have such beneficial outcomes, it is important that you receive massage therapy on a frequent basis for a short while so that you can retrain your muscles and create new muscle memory. That means your muscles will learn how to be both balanced and strong, will become more flexible through the action of massage therapy combined with both active and passive stretching, and will have a new chemical signature created from the increased range of motion, meaning you'll have longer lasting results.
*Sherman, K.J., Cherkin, D.C., Hawkes, R.J., Miglioretti, D.L. & Deyo, R.A. (2006) Randomized trial of therapeutic massage vs self-care book for chronic neck pain. Oral presentation at the North American Research Conference on Complementary and Integrative Medicine. Edmonton, Alberta.
*Treatment of Neck Pain Noninvasive Interventions. The Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders. Supplement. SPINE Volume 33. 2008