Pain is a common complaint among patients seeking medical care. If left untreated, pain can become chronic, significantly affecting patients' quality of life. An accurate diagnosis of the underlying cause of pain is crucial for effective treatment. Chronic venous insufficiency (CVI) is frequently overlooked by pain physicians. Moreover, many pain physicians lack sufficient knowledge about CVI. CVI is a common condition resulting from malfunctioning or damaged valves in lower limb veins. Symptoms of CVI, ranging from mild to severe, include pain, heaviness, fatigue, itching, swelling, skin color changes, and ulcers in the lower limbs. Recently, it has become more widely known that these symptoms can be attributed to CVI. Even slight or mild CVI can cause related symptoms. Pain physicians primarily consider neuromusculoskeletal disorders when assessing patients with leg pain, and often neglect the possibility of CVI. In clinical practice, when pain physicians encounter patients with unresolved leg pain, they must assess whether the patients exhibit symptoms of CVI and conduct tests to differentiate CVI from other potential causes.