What can I do to decrease the pain caused by legs venous insufficiency?

Compression stocking. Venous insufficiency, and its typical aching pain, can be treated conservatively with compression stockings, exercise, and intermittent elevation of the legs. If you have superficial venous insufficiency and varicose veins, you may get relief by a number of various treatment options of the varicose veins themselves.
Seek treatment. You need to seek treatment with a vein specialist as dr. Zimmet said. In the meantime, though, compression stockings, elevating your legs periodically throughout the day, and taking anti-inflammatory medicines can give temporary relief until more definitive treatment can be provided.
Seek proper eval/tx. Things you can do at home include aerobic activity, leg elevation, maintenance of ideal weight, and compression stockings. See a vein specialist/phlebologist for a proper evaluation, including history, exam and duplex ultrasound. A treatment plan can then be developed based on the findings in your case. Treatment is often very helpful in improving the venous insufficiency.
Venous insufficiency. use of a compression stocking during daily activities would be helpful. However, I would recommend an evaluation using a venous Doppler sonogram to determine the source of your venous insufficiency. Once that is determined a treatment protocol will be established which is a long-term better option than just using an relying on compression stockings.