some yoga exercises are fantastic for bad backs.
I have a deep curve of the back (basically where the spine curves in, mine is deeper than what it is meant to be) also i have sciatica which gives me cronic backache some days as well
but seriously i find yoga fantastic for it, also i find i have less pain in my back if i wake up 10 minutes earleir each morning and do some stretches then i sit on the floor legs crossed, sat up straight, shoulders relaxed, arms resting on my knees, inhale slowly, exhale slowly, slowly lower your head as if youve got a pen under your chin that you want to hold there, so slowly roll your head forward, the curl your shoulders, pull in your stomach and roll your torso and stomach slightly as well (your should feel pulling down your back) the slowly roll back up, do this three times.
then once youve done this, roll your head to the left, lift and rest your left arm on your right ear, then do the right side, do this three times as well.
then finally imagine your torso is cut off from the rest of your body from just under your ribs, imagining this move your torso round in a clockwise circle, as if its sliding on a table, circle clockwise 10 times, then anti clock wise 10 times.
after this do the chin,shoulder, torso rolling one more time. relax, inhale slowly, exhale slowly. sit for a minute. then get up.
these exercises wake your back and torso muscles up one by one and wake them all of them up. it helps energise them and helps them to work together and support each other.
this really helps to ease back pain as the muscles are all awake and work together supporting each other.
(it also really helps correct posture which can also result in back pains)
hope that helps xx