Hi Sarah Mae ~ Can I offer a suggestion? PLEASE don't use heat on your back. I was taught by a Neurosurgeon that heat draws blood to the heated area and causes swelling. It's already swollen in there if there's pain. Ice should ONLY be used, and 20 minutes at a time, every 2 hours. It's worked for me, and I've had spinal pain for 24 years. In fact I've had 2 open surgeries. So throw your heating pad away, and keep the ice handy. You'll be surprised at how much better your back will feel because it will reduce the swelling and numb the pain. Best of luck and God bless. Hugs, Lee