The causes of swollen, painful lymph nodes in the neck or other areas of the body are usually infection, vaccines or medications, sexually transmitted disease, immune system disorders and cancer, according to WebMD. When an individual is sick, the lymph nodes often swell, and this causes pain.
Common infections that cause swollen, painful lymph nodes include measles, ear infections, mononucleosis, strep throat and an infected tooth, according to Mayo Clinic. Additional common causes are HIV and skin or wound infections. Immune system disorders, cancer, tuberculosis, sexually transmitted disease and various rare infections are other possible causes.
An individual with painful lymph nodes should see a doctor if the lymph nodes continue to grow, have appeared without a clear reason, have been present for two weeks or more, feel hard or rubbery, or are unmovable when gently pushed on, according to Mayo Clinic. An individual should also see a doctor if the painful lymph nodes are accompanied by persistent fever, difficulty swallowing or breathing, night sweats, unexplained weight loss or a sore throat.
Lymph nodes that are swollen, painful, soft and easily moved are generally caused by infection or inflammation, according to WebMD. Swollen lymph nodes that are hard, unmovable and non-painful should be looked at by a health care professional.