From a Wall Street Journal online article:
Researchers in Germany published a study in the journal Pain in December showing that open-label placebos can help relieve chronic lower-back pain, 
replicating a 2016 study. A similar study by University of Colorado, Boulder researchers found that placebo saline injections reduce chronic lower-back pain.
Two other recent studies showed placebos openly given to cancer patients helped relieve cancer-related fatigue. And a forthcoming study by German researchers found openly giving placebo to elderly patients helped improve knee pain.
More researchers are looking at the idea of placebos—substances that have no actual pharmaceutical effect—as an alternative to traditional pain medications, which can be ineffective and carry significant side effects. Placebos might have particular potential for difficult-to-treat conditions like chronic back pain, cancer-related fatigue and symptoms of irritable bowel syndrome, researchers hope.
As many as 30% to 50% of chronic pain patients will respond to placebos, research suggests. And new studies are helping to identify genetic and brain differences that make certain people more likely to respond.
Sleep problems may decrease the likelihood of recovery from chronic low 
“Another behavior change is physical exercise,” Pillemer said. “A paradox of pain is that exercise helps reduce it, but it’s difficult for people in pain to think about exercising. So they don’t exercise, they get more sedentary and the pain increases; it’s a vicious circle. So how do you get people to actually change their behavior?”
Dr. Grace Dammann, medical director of the Pain Clinic at Laguna Honda Hospital, and seven of her colleagues talk about what does and does not work in the treatment of chronic pain. She talks as both a patient and a provider. There is also a discussion of various non-pharmacologic and complementary medicine modalities to treat pain.
