A 48-year-old woman is evaluated for a 6-week history of persistent low back pain. The patient is a nurse and has had continuous pain ever since helping lift a patient. The pain is localized to the lumbar back, is bilateral, and does not radiate. She has not had fever or bowel or bladder dysfunction. The patient was involved in a motor vehicle accident 10 years ago and sustained a back injury that has subsequently healed. Medical history is otherwise unremarkable, and her only medication is as-needed naproxen for pain control.
On physical examination, vital signs are normal. BMI is 27. The general medical examination is normal. Musculoskeletal examination shows pain induced with palpation over the lumbar paraspinal muscles. Range of motion with back flexion and extension is limited. Results of the straight-leg raise test are negative bilaterally. Lower extremity muscle strength and reflexes are normal.
Which of the following is the most appropriate treatment?