I get them I find a nice warm bath helps followed by an ice pack on for 20 off for 20. Mine seem to be stress related so I have also found A warm cup of tea and a vent fest to Hubs or my BF helps get the stress level down and Yoga for stretching.
Follow up - I went to the chiro for the first time ever yesterday and he did a great job sorting out my back. Sadly because I haven't had regular adjustments it's already slipped back to about the place where it was (though not quite... it does feel a little better still). I go back on Friday for another adjustment.
Re: Anyone having bad back spasms?