I know the title sounds almost contradictory, but let me introduce myself...
I'm male, 21, from Italy, and used to be physically inactive during my teens. That means, although from time to time I did a few things, I didn't engage in any
regular sport or exercise (I started a few, but finished after 3-4 months everytime since, for some reason, I get bored quickly, lose my enthusiasm).
Initially (until age 18) it seemed that nothing was wrong since I still had a pretty normal body (
60kg for 1,74m), but then I started to notice how, despite maintaining the same eating and moving habits, the body changed.
When I was 20 (amidst college, exams, etc. I probably moved even less than before) I reached
75kg, and that's when I decided to take initiative, be responsible, act and do some regular exercises.
For some unfortunate reason that nobody was able to explain as of yet, I damaged my spine while trying to loose weight.
Probably I exaggerated: as a matter of fact, I seemed to lose about 1kg per day following that diet... basically I was running and exercising all the day for 2 weeks, until one day I did a stretching posture that caused severe chronic pain from the spine.
The pain, which is typical of spinal disc herniations, hasn't disappeared yet (I'm having it since exactly one year now), but despite MRIs, X-Rays, and everything else, no doctor has actually been able to tell me what I have (or to confirm whether it is actually a spinal disc herniation).
All they say is "It's just muscle pain. It will go away after some time!" or "You're a hypochondriac, stop wasting our time!"

My personal gut feeling tells me that while I did that stretching posture I triggered some process that is causing a spine disc to herniate in a very slow process (which is why the doctors cannot find it out).
Anyway, assuming that I damaged my spine,
I shouldn't do any exercise at all! I feel the pain very strongly when I run (pressure on the vertebra?), which strengthens my assumption that the spine was damaged.
I didn't do any exercise at all during this year (since June 2007), but I still manage to walk long distances everyday, and I trimmed my eating habits (five small meals a day).
Despite walking and eating less, I keep getting fatter and fatter everyday.
Currently, I weigh
78kg, and I start feeling bad noises in the blood.
The worst news is that, according to what I read,
additional weight puts even more pressure on the spinal discs!
What can I do now? Have I triggered a process of automatic self-destruction?
Is there any other way I can loose weight?
I'd be very grateful to hear your advice!
Thanks in advance!
EDIT: for the American readers...
I currently weight 172lbs and am 5' 8.5" tall/short