For chronic back pain unresponsive to physical therapy, a stepped medication approach is common. Over-the-counter options like ibuprofen, naproxen, or acetaminophen can manage temporary flare-ups, but long-term daily use is not recommended due to side effects. For long-term prescription management, doctors often consider medications like duloxetine or gabapentin, which help modulate chronic pain signals. Low-dose muscle relaxants, like cyclobenzaprine, may be used for intermittent spasms. Since your pain is persistent, I highly recommend consulting a physician or pain specialist. They can safely tailor a long-term prescription plan and determine if further diagnostic imaging is necessary.