There is a high likely possibility of axial spondyloarthritis as per your reports. Usually seen in young males. All your spine bones develop inflammation at joints leading to pain at 2nd half of night or early morning associated with stiffness in the back. Usually to confirm; we perform HLAB27 testing and also MRI of pelvis to look for sacroilitis. One test is positive. Likely to be spondyloarthritis.
Next Steps
Kindly do MRI SI joints ( pelvis) STIR sequence
CBC/ ESR/
CRP /
LFT / RFT
Health Tips
May start to take painkillers and physiotherapy temporarily; you will need to be started on arthritis treatment as early as possible.