A 46 year old man while in the gym had sudden onset of back pain

A 46 year old man while in the gym had sudden onset of back pain. He presents at the A&E with lower back pain. He has been given oral analgesia and now feels better. All examination is normal. What is the most appropriate advice for him?+

A. Bed rest
B. MRI spine
C. CT scan spine
D. Continue moving