Carol's pick: Johns Hopkins Health Alert: Can massage help back pain? A nice overall review of managing chronic back pain that is not from a specific injury. It cited both immediate and long-term effectiveness of massage, though indicating that long-term relief might require multiple massage: "Studies on massage typically involve a course of therapy, not just one massage. For instance, in a study from the Archives of Internal Medicine, among 262 people with chronic back pain, patients who received one massage per week for 10 weeks reported less back pain up to one year after the study ended. . . . A recent Cochrane review of 13 clinical trials that included over 1,500 participants with chronic back pain found that massage therapy was more effective at reducing pain and improving function when participants also incorporated stretching exercises and basic education about behaviors (like poor posture) that contribute to back pain."

Imamura M, Furlan AD, Dryden T, Irvin E. Evidence-informed management of chronic low back pain with massage. Spine J. 2008 Jan-Feb;8(1):121-33. Review. PMID: 18164460 

A review article on the helpfulness of massage to manage low back pain gives some instances of better outcomes and some of equal outcomes compared with other interventions.