I seem to develop numbness in my hands every night during my sleep. After I get up or change my sleeping posture it becomes normal. Is this normal?

See your doctor. It is possible that you may have carpal tunnel syndrome. Your doctor will take a detailed history and perform a physical exam. If your doctor determines that you have carpal tunnel syndrome, there are multiple treatment options available.
Alternatively. You could also be having irritation to your spinal cord that worsens with bending your neck.