I have another question...have you had any pain or ache on your hip? If you're unsure, place your thurab on your greater trochanter (that's the protrusion of your femur where the top meets your pelvis) and see if that hurts.
Chances are, if you experience pain there, or along a line from the trochanter to your lower back, then it may not even be related to your spine at all, but your piriformis.
The piriformis is a muscle that runs from your hip to your lower back under the glutes. When this muscle is tight or inflamed, it will impinge on your sciatic nerve, which results in the same problem you describe.
If it's your piriformis, there are certain stretches you can do to relieve the pain. You can find them all online. Another trick is to lie flat on your back & place a tennis ball under each buttock, rolling them along the line of the muscle.
Good luck & keep us posted as to what the problem really is.