Soreness in the right shoulder may be due to physiological reasons or pathological reasons, such as lactic acid accumulation, frozen shoulder, cervical spondylosis, etc. 1. Physiological reasons: it may be that frequent horizontal lifting of the right upper limb or when the right upper limb needs to be lifted due to weight-bearing, it will cause repeated movement of the deltoid muscle of the shoulder, which generates lactic acid. When lactic acid metabolism is not timely, it will lead to a large amount of lactic acid staying in the body, thus causing the symptom of physiological soreness of the right shoulder, which is usually relieved after rest. 2. Pathological causes (1) Frozen shoulder: trauma, strain, accumulation of injuries, etc. lead to degenerative changes in the right shoulder joint and its surrounding soft tissues, which can be manifested as soreness and swelling of the shoulder, and with the aggravation of the condition, it will be manifested as pain and functional limitation. (2) Cervical spondylosis: degenerative changes in the cervical intervertebral discs produce herniated discs, which irritate or compress the nerve roots in the neck. It may trigger the nerve in the right shoulder to be irritated, thus triggering the symptoms of soreness and swelling. There are other causes of right shoulder soreness, such as trauma, cholecystitis, etc., if rest does not relieve, it is recommended to consult a doctor in a timely manner, improve the relevant examination, clear the cause of the disease, and then follow the doctor’s instructions for targeted treatment, so as not to delay the condition.