Lay on your back with knees bent and arms at sides with palms facing down as in the image. Tuck your chin into your sternum as you lift your head up slightly (you should not be straining your neck). If uncomfortable on your neck, keep your head down. Now wave your arms up and down. Lifting and lowering your arms 2-3 inches without touching the table. Repeat for 1-2 minutes. Eventually, increase the time by 2-3 minutes.
DISCLAIMER: Please consult a healthcare professional before attempting exercise.