Lumps at the bottom of the neck without pain may be caused by goiter, sebaceous cysts, lymphadenitis and other diseases. 1. Goiter: the lack of iodine and other trace elements can lead to relatively excessive secretion of thyroid-stimulating hormone, which will promote the excessive enlargement and proliferation of thyroid cells, resulting in a lump, which is usually painless. 2. Sebaceous cysts: Sebaceous gland ducts blocked for various reasons, will make the body’s secretion stagnation, which triggered a small lump, can appear in the neck, most of the sebaceous cysts do not feel pain. 3. Lymphadenitis: pathogenic bacteria from the skin, mucous membranes or nearby infectious lesions invade the lymph nodes, which in turn leads to localized infection of the draining lymph nodes, swelling, which will form a lump without pain. Lump below the neck without pain may also be seen in lymph node tuberculosis, thyroid cysts and other diseases, if there is a lump below the neck without pain symptoms, persistent and unrelieved, you need to go to the hospital in time for examination, clear cause of the cause of the disease to do treatment.