Spacemonkey, it'd be great to hear how you get on, as i am still trying to work out what to do about a back problem i've had for six months or so. sharp burining pains when changing position like yours, and i'm about the age you were when you first had it. It was worst when it started (after trying to do a tortoise/crab outside on the grass!), and lasted a few weeks, then dies down a bit, but recurs whenever i forget about good posture again, which is frequent as i'm lazy. At the moment it's fine, but i'm sure it will return. I have recently taken up a soft martial art and it seems to help a bit, my back is stronger anyway. My instructor told me to put a ginger poultice on it ... i haven't because i'm lazy but you might like to find out about it.
cheers,
-ian
cheers,
-ian