I get muscles spasms all the time. They used to require chiropractor manipulation and stimulation (from the these electrode thingies) and medications. Now, I don't use any meds for the pain because I've learned how to prevent further injury.

Things I do:
* Stretch (when waking & going to sleep)
* Hot baths (when back becomes stiff)
* Proper posture (lifting, moving, and sitting techniques)
* Resting (recognize and respect when I'm unable to complete a task)
* Breathing exercises (when pain starts and while moving)
* Bracing self when needed
* Massage chair
* Keep stress under control

I think the most important thing is preventing further strain, pain, and injury. Once the pain subsides and you keep doing the suggestions above, you'll not need as much (or not at all) medications to manage your pain.