Arachnoiditis is a rare clinical entity that usually presents with severe debilitating radiating pain that can pose a challenge in diagnosis especially in areas without appropriate imaging modalities. We present a 26-year-old male with progressive lower back pain with radiation to the lower extremities, aggravated by movement and touch. We diagnosed idiopathic arachnoiditis based on cerebrospinal fluid analysis and magnetic resonance imaging. He was managed with a 5-day course of methylprednisolone and analgesics with a good outcome. Severe back pain without a specific cause in a young patient should be investigated with proper imaging modalities and lumbar puncture if warranted to evaluate the cause.