A soybean-sized thing inside the left side of the neck may be a normal lymph node, or it may be a subcutaneous cyst or thyroid nodule. 1. Lymph nodes: Lymph nodes are the body’s immune organs, and the neck is richly distributed with lymphatic tissues. If there is no redness, swelling, pain, or tendency to increase in size, the lymph nodes will have no effect on the body and do not require treatment. 2. Subcutaneous cysts: cysts caused by poor blood circulation in the subcutaneous tissue will have hard knots under the skin, and in severe cases, the pain will be broken, the general effect of drug treatment is not good, you can take surgical treatment, the hard knots do not have to deal with the enlargement and pain, observation can be. 3. Thyroid nodules: the thyroid gland is distributed in the front part of the neck, when the left side of the thyroid gland grows nodules, you may feel the soybean-sized nodules in the left side of the neck, you need to go to the hospital to do thyroid ultrasound. According to the classification of the thyroid gland to determine whether to conservative observation or do further treatment. When the left side of the neck with soybean-sized things can not determine the cause, you need to go to the hospital, do the relevant examination, and follow the doctor’s instructions for treatment.