M.S. pain

I was diagnosed with m.s. when I was 16 (now 27).  i am a male of hispanic decent.  I was treated in the hospital with steriods through my i.v. for one week.  I got back  to normal.  The left side of my body was tingling.  My MRI showed lesions, but my neurological test was normal and my spinal tap came back as inconclusive.  I fought the possibility of having M.S. for a few years and refused to take the betaseron.  One year ago i was put on rebif only to be taken off of it a few months later cause my platelet count dropped significantly.  Anyways, I'm about to start back on Rebif amd also am getting a prescription for oral steriods.  My questions are why does my doctor wait so long only to tell me that the steroids will be no good at this point and also, I had an MRI done recently of my brain, t-spine, and  c-spine cause my back has been killing me for about a year now.  The MRI came back normal except for one new lesion in my frontal lobe which the doc says is pretty "silent".  I've tried vicoden, neurontin, percocet, advil, alternating hot and cold, muscle relaxers, and even excersize but noting works but the narcotics work. What do you think it is?  M.S. or something else? What should I do to stop this constant agonizing pain?