I am also having this same exact type of pain, but I am also getting numbness and tingling(pins and needles) when I sit down. In the past 2 weeks I have had an MRI, small bowel study, ultra sound, and nerve conduction study done. In the MRI, they found that I have 4 minimally bulging disks in my lumbar, some scoleosis, some back arthritis, and abnormal nerve problems in both my legs and my right arm. All of this basically leads to pinched nerves in my back.
I have not had an episode recently when I hurt myself, but the pain came on gradually and got to the point that I could not lift my right leg high enough to put pants on myself. Then the pins and needles started and my leg function came back but with weakness. My G.I. said that there is condition with crohn's, in which inflammation in your spine can cause the nerves to become constricted and inpinched. He said that if you have had a previous injury there in the past, then you are more likely to have this happen to you. I pinched 3 nerves in my back when I was wrestling in high school. I saw a chiropractor back then and from time to time throughout the past 11 years, but having only really treated it with physical therapy and massage. Let us know how you end up treating it. I am trying to avoid another surgery at all costs.