Chronic pain is a sensory experience that produces suffering and functional impairment and is the result of both sensory input as well as secondary adaptation of the nervous system. The sensitization of the nervous system to pain is influenced by physical activity (or inactivity) and medication exposure. Medication taking and physical activity are behaviors that are increased or decreased by positive and negative reinforcement. Patients often have comorbid psychiatric conditions at presentation, including addictions, mood disorders, personality vulnerabilities and life circumstances that amplify their disability and impede their recovery. Behavioral conditioning contributes to chronic pain disorders in the form of both classical (Pavlov) and operant (Skinner) conditioning that increases the experience of pain, the liability to ongoing injury, the central amplification of pain, the use of reinforcing medications such as opiates and benzodiazepines, and behaviors associated with disability. The term 'abnormal illness behavior' has been used to describe behaviors that are associated with illness but are not explained physiologically. Behavioral conditioning often amplifies these abnormal behaviors in patients with chronic pain. Addiction can also be seen as a behavior that is reinforced and conditioned. The same factors that amplify abnormal illness behaviors also increase the liability to addiction. Psychiatric comorbidities also complicate and amplify abnormal illness behaviors and addictive behaviors and further contribute to the disability of chronic pain patients. Model interventions that reinforce healthy behaviors and extinguish illness behaviors are effective in patients with addictions and chronic pain. Maladaptive behaviors including addictive behaviors can be used as targets for classical and operant conditioning techniques, and these techniques are demonstrably effective in patients with chronic pain and addictions.