Acvording to your symptoms and according to mri reports. There is loss of curvature of spine and disc prolapse at lumbar region and edema is also seen . But according to your age these conditions is little bit uncommon if you have no history of injury or work related stress. Hla b27 is also advice for mri reports but i advice dont do that. First you have to consult a near about physiotherapist. If u come to greater noida then visit my clinic indian spine and pain care center