I recently had lower back surgery on my l-4 disc.  A week and a half after surgery my back statred hurting more than every.  I was ingnored by my doctor and his staff.  After being post/op 7 weeks he FINALLY did a MRI and said I was doing to much when in reality I was doing nothing because the pain was so terrible and dibilitated me (I also have a 3 and 5 year old).  HE said bed rest for 3 months not to get up but to use the restroom. THat following day I decided to seek a second opionion that doc knew right away it was discitis.  I go for my biopsy tom.  This is a very serious condition and if you are having problems be consistant with your doc and don't be afraid to get other opinions.