A sliding lump on the left side of the neck may be an enlarged lymph node or a subcutaneous swelling. You should go to the hospital and take targeted treatment after completing relevant examinations. 1. Enlarged lymph nodes: the diagnosis can be made by palpation and ultrasound of the lymph nodes in the neck. There are many reasons for the enlargement of lymph nodes, which can be caused by bacterial, viral and fungal infections, as well as drugs and malignant tumors. We should ask for a detailed history, complete the relevant examination, and take targeted treatment after clarifying the cause. 2. Subcutaneous swelling: may be sebaceous cysts, epidermal cysts, lipomas, etc., palpation and local surface mass ultrasound can assist in the diagnosis, if you need to make a clear diagnosis, need to be surgically resected to do pathological tissue examination. If you touch the neck sliding swelling, please go to the hospital in time to avoid delaying the condition.