Avascular Necrosis, Aseptic Necrosis, Ischemic Necrosis, Osteo Necrosis

Is there any possiblity that my doc will ever find the cause of my AVN???

I was diagnosed at age 24.  At 25 I underwent a THR (total hip rplcmnt) because the hip was completely destroyed.  Almost a year later the AVN traveled to my right hip ruling out injury.  He ran many tests but everything came back normal.  I am going on 30 now and I have developed chronic, severe pain in my thoracic spine.  I have had two MRI's done with each one worsening.  The doc is unsure what it is.  He described it as a black circular area on my spine.  What does that mean???  Is it possbile the AVN is there too???  I am scared as I am very young, on morphine, and have three little boys in my life that need there mom.  I want to go back to work in the nursing field, but wonder how much this is going to affect the rest of my life.  All normal causes of AVN do not relate to me at all.  Should I find another doc more knowledgable with this disease, if I can even find one...  most docs don't even know what it is or familar with it at all.