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.
Constipation distends the intestine with retained stool. This can lead to discomfort, bloating, and a sensation of fullness that can be felt across the entire abdomen and can even extend into the back region causes back discomfort. However this back pain if it is from constipation will probably be just dull and not very severe.