Brief Answer:
Evaluation through a neurophysician....
Detailed Answer:
Hi,
I went through the details with diligence. You been suffering with leg pain for 4 years now and the spine surgery was a year ago. Therefore I assume the doctors have ruled out any other spinal nerve root compressions that are known to cause similar pains.
Now, there are few other conditions that are known to cause this type of leg pain. The most common ones are related to nutritional deficiency as well as hormonal changes. Rarely this type of pain is due to vascular disease involving lower limbs. In my opinion, you should consider consulting a neurophysician to evaluate for these problems. The doctor can run some tests to tests for nutrients, blood sugar as well as thyroid hormones. Besides these if deemed necessary, he/she might also order for doppler study of lower limb blood vessels which will identify vascular deficits if any.
Based on the description, your problem doesn't seem serious. So you can plan for appointment with the doctor.
Hope this helps. Let me know if you need clarifications.
Wish you a Happy New Year in advance!!