Neck pain is fairly common, but that which is accompanied by swelling on the back of the neck is not. In addition, visible neck swelling along with pain could indicate trauma or infection, though you may not even know you are suffering from those conditions.
Neck pain can be the result of trauma, chronic conditions such as arthritis, illness, improper ergonomics, excessive exercise, poor posture or a car accident. By itself it is not necessarily a serious condition.
Neck swelling could be a result of internal inflammation due to an autoimmune disease such as arthritis, as well as swollen lymph nodes, infections or trauma. Visible inflammation is more unusual, according to Dr. Rob Gottesman, a Colorado Springs chiropractor. This would more likely be the result of an infection.
Neck pain and signs of inflammation, such as redness, soreness, stiffness and tenderness to the touch, might be an autoimmune disease flareup, such as from lupus, arthritis or fibromyalgia. Any neck pain with visible inflammation should be checked by a doctor, who will probably do an X-ray of the affected area to determine a diagnosis.
Sinus infections can also cause neck pain, and staphylococcus (staph) infections affecting the skin might result in a boil or abscess. One of these on the back of the neck will be red, sore and appear inflamed and can worsen and spread to other areas of the body.
The posterior (back) neck muscles develop trigger points, according to Valerie DeLaune, Trigger Point Therapy expert. A trigger point pattern in the suboccipitals (above the ears) can cause soreness at the skull base. In the splenius cervicis (back side of neck), it will hurt up the back of the head and at the bottom of the neck.