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.
The main cause of neck pain is tension. During periods of intense anxiety, your muscles tense up dramatically. Muscle tension tightens the muscles, especially in the shoulders, back, and neck. The more anxiety you experience, the more your tension may cause significant pain and discomfort. A related issue comes from the mindset of those with anxiety. Many people get muscle tension in their neck during times of stress.
Causes of a Lump on Back of the Neck. 1. Injury to a muscle or tendon, from an accident or strenuous movement, can result in a lump on the back of the neck. The lump may be the muscle itself as it moves in place when damaged. Our muscles and tendons maintain our body shape. You may feel pain, neck stiffness, or have difficulty moving your neck.