Musculoskeletal Strain: This is often the most common cause of recurring pain in the neck and back, due to overuse, poor posture, or injury. The pain is typically localized to the area of strain and can be exacerbated by movement.

Herniated Disc: A herniated disc in the cervical or thoracic spine can cause recurring pain on one side of the neck and back, especially if the disc is pressing on a nerve.
Degenerative Disc Disease: Wear and tear on the spinal discs can lead to recurring pain in the neck and back, often worse with movement or activity.
Scoliosis or Spinal Deformity: Abnormal curvature of the spine can cause uneven wear and tear, leading to recurring pain on one side of the neck and back.

Pulmonary Embolism: Although less likely, a pulmonary embolism can cause sudden, severe pain on one side of the back, and is a life-threatening condition that requires immediate attention.
Aortic Dissection: A tear in the aorta can cause severe, tearing pain in the back, often radiating to the neck, and is a medical emergency.
Spinal Infection or Abscess: Infections such as osteomyelitis or discitis can cause recurring pain in the neck and back, and require prompt antibiotic treatment to prevent serious complications.

Pancoast Tumor: A rare type of lung cancer that can cause recurring pain in the neck and back, often accompanied by other symptoms such as arm weakness or numbness.
Multiple Myeloma: A type of blood cancer that can cause recurring pain in the neck and back, often due to bone lesions or fractures.
Ehlers-Danlos Syndrome: A rare genetic disorder that can cause recurring joint pain and musculoskeletal symptoms, including neck and back pain.