You are 26 years old and are suffering from retrilistheses with prolapsed disc with most likely spasm of the back muscles, which is causing the pain along with radiculopathy
You need to rest, take muscle relaxants, hot fomentation along with short wave diathermy and IFT if possible, vit B12 supplements and pregabalin
Once pain subsides try spinal flexion exercises along with daily walk, use lumbar belt to support the spine.
this problem may get aggravated due to further increase in lumbar curvature,but it may not be always so if you exercise and maintain the right posture. You need to careful while lifting heavy weights or any form of physical activity which causes pain.