Pain is the most common and debilitating side effect that patients with cancer experience. Contributing factors include the disease itself via tumor invasion on surrounding tissue and bone; nerve compression; treatments including chemotherapy, radiotherapy and surgery, especially chemo-induced peripheral neuropathy (CIPN), which can be disabling; and aromatase inhibitors that can cause persistent diffuse joint pain. In addition, pain that “breaks through” continuous pain medicine can be difficult to predict and control.