The pain in the right lower limb on standing and walking could be due to one of two causes:
a) The blood supply to this limb is poor. This can be ascertained by an examination of the pulses in the lower limb and by checking the capillary circulation in the toes.
b) There is pressure on the nerves leading to this limb. This pressure is commonly in the lower back and is usually produced by backward bulge of the shock-absorber discs between the bones forming the spine.
I suggest you consult your physician and request a checkup to determine the exact cause. Appropriate treatment can follow.