Hello SurferIan:

You probably just aggravated a nerve. I had the same problem. I had a microdiscectomy at L3-L4 9 weeks ago. I was fine for 3 weeks. Then my right leg was throbbing,tingling, and felt like it weighed 100lbs.Went back to the doctor and I had to have a myelogram,ct scan, and x-rays. Every thing looked fine. Said I aggravated a nerve. It just happens sometime. My doctor told me to walk as much as I could stand. Do the stretching exercises. He also put me on a medrol dose pack (steriods).
Ask your doctor about that. It will get better.Hang in there SurferIan!