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.
Back pain is caused by a pinched nerve in your back so there is no healing of that. When a nerve is pinched it tightens up muscles around it to trap it in that pain. To get rid of the pain you have to free up your back muscles to release the nerve and here's how to free them up: Back: (do while sitting)