There are many factors that can cause lumps in the neck overnight, such as localized soft tissue injury of the neck, enlarged lymph nodes, sebaceous cysts, etc. 1. Local soft tissue injury of the neck: when the soft tissue around the neck suffers from external collision or slippery abrasion and injury occurs, it will cause congestion, edema and other reactions of the soft tissues, thus appearing the performance of neck lumps. 2. Enlarged lymph nodes: when the human body suffers from bacterial or viral infections, it will lead to aseptic inflammation of the lymph nodes in the neck, which will lead to the symptoms of neck lumps. 3. Sebaceous cysts: If the body’s metabolism is too vigorous, it will make the neck of the excessive secretion of the cortex, thus accumulating in the mouth of the hair follicles, can not be eliminated in time and the formation of lumps. In addition there are many other reasons such as mosquito bites, etc., such as a long time without relief, should go to the regular hospital to check the cause and targeted treatment.