Muscle weakness and pain in calf since 4 years suggests nerve compression in your lower back. For ruling out vein issues venous echo would be required which can be suggested by cardiologist.
Next Steps
Kindly visit cardiologist for checking if it's venous issue. If that's ruled out then you will need to visit nearby physiotherapist for further evaluation and treatment.
Health Tips
Avoid hot packs on leg or back. Avoid forward bending movements from back. Avoid weight lifting from floor.