Constant Sciatic Pain

I have had sciatic pain for years and have had steriod injections, physcial therapy and currently on Naprosyn.  This sciatic flare up has gotten worse.  I had an MRI done three weeks ago came back normal, no slipped disc or bulging disc.
Walking sends pain down my buttocks, leg and into the ankle and bottom of my foot. I find myself dragging my left leg or tripping due to weakness in the ankle.  I have a tender spot in my lower back all the time.  Doctor has given me a twelve week recovery time but I am in my  last week of recovery and the pain has not subsided.  Doing back exerecises but it only relieves the pain for a short period of time.  Tired of being in pain everyday and not able to walk like I used to.  What is next ?

[sweetpeamax]

posted to wrong community should have been posted to neurology