muscle spasm
"I have been living with chronic neck, back and migraine pain for several years now.  In the beginning, my doctors had me go to physical therapy, take ibuprofen, or aspirin.  None of these things ever really helped.  After trying Flexeril and numerous anti-inflammatories, my pain management doctor did an MRI and found that among the many tension knots and twisting of my spine, I had bulging disks in my neck.  He gave me Zanaflex to take at night.  It knocks me out within 20 minutes but helps relax my back and neck so that I can get restful sleep - been on it for 3 months now!  I highly recommend it for continuous back pain and it's even helped with my migraines.  Be ready for bed though - very powerful!"