I had back surgery for a herniated disk (L5,S1) area of back, and have permanent nerve damage and continue to have to take pain meds for the pain (Lyerica , Wellbutrin, and a small doze of oxecodine. I have ED perhaps due to the meds, and I have been prescribed Viagra and Cialis to help with the ED. My question is that when I take Viagra or Cialis I end up having severe pain in my legs and back similar to when I first injured my back is this common?