What Causes Pain In Buttock Down The Calf Muscles?

I have meniere's disease, diabetic, I have both knees totally replaced. I was in P.T. when the pain continually got worse & therapist referred me back to my doctor, who referred me to a spine specialist, at first in his office I had 2 injections in the back, which did nothing, Then I went in for spinal lumbar injections which lasted 3 days, now I'm on meds & the pain is ecrusiating at times, where I can barely walk. Pain goes to buttocks, down to calf & then to toes. Which makes it numb, plus I have drop left foot & all this happens on my right side. Once I take meds & its to a dull ache I go & take a walk. I just want this to go away, it came on suddenly & I just want relief.