Brief Answer:
Hi,

Detailed Answer:
There may be multiple reasons for pain leg, like peripheral arterial disease, peripheral neuropathy, injury to muscles of leg, overuse or sternous exercise of leg , leg vein thrombosis etc. Still. the pain in leg along with cooling in foot may be most commonly due to peripheral arterial disease resulting in narrowing of arteries of leg & foot, resulting in less supply of blood to leg & foot, hence the presence of symptoms.
In these cases, the common cause of narrowing of arteries is atherosclerotic phenomenon due to deposits of fatty tissue etc. in the lining of arteries & hence symptoms of reduced blood supply to the organ. Other cause may be Burger"s disease or Rauynauld" phenomenon etc.
Diagnosis, depends on finding the extent of narrowing of arteries by DOPPLER BLOOD Flow studies of arteries of lower limb & determining the cause like diabetes, hypercholestraemia etc.
Treatment depends on the cause like diabetes or hyperlipidemia etc. Some times it can be managed by change in habits like quitting smoking, taking healthy diet with restriction of fat etc. Some times, the symptoms can be managed by physiotherapy & medicines etc. However, if the condition is not relieved by these measures, then surgery may be the only option for restoring the adequate blood supply to the legs & foot etc.
Thanks.

---