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.
The muscles get tight, hard, and painful. Neck spasms may happen from an injury, overuse, poor posture, or stress. For example, it is common for people who do a lot of computer work to get a stiff neck. Spasms may even occur from an uncomfortable night's sleep. The muscles in your neck feel hard, tight, and painful.