There is a small ball inside the right side of the neck, the possible causes are lymphadenitis, cysts, tumors and so on. 1. Lymphadenitis: a small ball inside the right side of the neck may be caused by lymphadenitis. Lymphadenitis is usually a benign lesion of the lymph nodes caused by bacterial infection, which is mainly manifested by enlarged lymph nodes, localized pain and tenderness, and is prevalent in the neck and armpits. 2. Cysts: a small ball inside the right side of the neck may be caused by a neck cyst. The main causes of neck cysts are genetic factors, dietary factors, environmental factors, trauma and so on, all of which may lead to the occurrence of neck cysts. 3. Tumor: a small ball inside the right side of the neck may be a lymphoma of the neck. There are a lot of lymph nodes in the neck, if the neck grows tumor, it may be lymphoma of the neck. There may be other reasons for a small ball inside the right side of the neck, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.