Numb lower body, MRI ok

[Jake24]

For about 6 weeks now, my lower body has been a bit numb and had the, for lack of a better term, "pins and needles" feel to it.  This started after I took a jog one day without really stretching beforehand.  The next few days I had severe knee pain which I morphed into more or less the entire lower half of my body feeling numb nonstop.  A few days ago my other knee started to be incredibly sore too.  I have a history of back problems (nothing more than having a sore back for the past few years though)
Figured it was a slipped disk so went and got an MRI but everything looked fine.  Obviously I am a bit concerned about this and have absolutely no idea what it could be.
I am going to see a neurologist in the next few weeks who can hopefully shed some light.

Any thoughts or ideas on what the problem could be.  I realize it is impossible to diagnose via email but I am concerned.

Thanks!

[Maddy1443]

Jake did you ever find out what your problem was?

[mateone]

Jake24 - Are you around?  Could you please update on your progress as I have the same symtoms as yours for the last 6 months.  I posted a question for you about 6 weeks ago but have had no response.  Grateful for a response.

[mateone]

I ruptured my right achilles tendon about 5 months ago and, as a result, my foot was in cast and had to use two crutches to move around.  After about 3 weeks on crutches, one evening I noticed my right leg was numb and by following morning the numbness had spread to the entire body below the waistline.

It is now over 4 months since the onset of the numbness and it still remains.  The achilles tendon has healed and crutches were discharged about two months ago.  However, the numbness in lower body remains has increased somewhat and additional problem of stiffness in both feet and legs has also emerged.  Have had several neurological/physical examinations that are normal.  (Therefore, the numbness below my waistline is really more of a sensory disturbance rather than true numbness when entire feeling is lost.)   MRIs of entire spinal cord and the brain is also normal.  

CSF analysis showed a slightly high protein level which in itself was non specific.  Other CSF analysis tests, various blood test, chest and lumber x-rays were all normal.  Somatosensory evoked potentials in the arms were normal but the ones for the legs were abnormal but not in a way that allowed them to be specific as to pathology or the location of the problem.

Would be grateful for any advise from anyone and, in particular, from Jake24 whose symtoms appear to be similar to mine.