A hot or fiery sensation in the leg is usually associated with nerve damage. The common ones are compression of the sciatic nerve, such as a herniated lumbar disc compressing a nerve or pear-shaped muscle syndrome. If both legs have this symptom and it is more obvious when walking more, it may be caused by spinal stenosis. There are also viral infections, such as shingles, that can cause this problem. Therefore, if the pain is very pronounced and prolonged, go to the hospital first to have the diagnosis of the disease clarified. If it is caused by herpes zoster, you should take antiviral medication, such as acyclovir, either orally or by intravenous infusion. If it’s caused by a lumbar disc herniation alone, you need to do a CT of the lumbar spine to see the specific severity of the lumbar disc herniation itself to choose the treatment.