My fiance has been getting swollen calves ankles and feet. they become tender with spider viens diff walking sever pain. what could this be. ?

Need exam & tests : She could have chronic venous insufficiency , phlebitis , weakness of heart , low proteins , etc, she need to see her doctor for tests and treatment.

Consider vascular: Consider having non-invasive vascular tests run. These are ultrasound (dopplers) that check both arterial and venous flow into the extremities. With swelling and pain with a history of prominent veins, it is important that peripheral vascular disease is ruled out. Talk to your primary care physician.