Studies show that 80 to 90 percent of back pain patients do get better on their own. Most do so in the first six to eight weeks. Three months seems to be a cut off point for some patients.
According to a study from the Netherlands there isn't much change in patient outcomes between three and 12 months. Two of the main factors used to predict outcome were duration of pain and having a paid job.
It seems that waiting too long at the outset of pain leaves the patient at risk for chronic pain later. Patients who didn't have a job were three times more likely to have continued pain at the end of 12 months.