Active and Passive Immunity. Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen.
Lower back tightness can cause muscle twitching, pain and reduced range of motion. Lower back muscle tightness is the cause of a muscle spasm. This can be brought on by a strain, overuse or muscle weakness, according to BetterMedicine.com.
Subscribe to our Pain Management Advisor e-newsletter for tips to manage pain. A common cause of back pain is injury to a muscle (strain) or ligament (sprain). Strains and sprains can occur for many reasons, including improper lifting, poor posture and lack of regular exercise. Being overweight may increase your risk of strains and sprains affecting your back. Back pain can also result from more-serious injuries, such as a vertebral fracture or ruptured disk; from arthritis and other age-related changes in your spine; and from certain infections. Possible causes of back pain include: 1  Muscle strains.