Although prevention of back injury is preferable, there are many stretches for lower back pain.  Always be sure to support your spine.  This includes strengthening the muscles that surround it for a strong core, which will keep your back in top shape and avoid pain.  Do not subscribe to the “no pain, no gain” motto when doing back stretches.  Forcing your back to stretch or over-stretching could cause further damage that may not be reversible.  Be gentle with your back and nourish it back to health by gently strengthening your core muscles and before long your back pain will disappear.