Interesting that your xray report was specific about the cause of the loss of lordosis. I have your same Xray findings ("complete loss of cervical lordosis") but it was the rheumatologist that explained to me that muscles spasms were the likely cause. He believes my spasms are in response to inflammation caused by my Ankylosing Spondylitis.
In simple terms, and as I understand it, here's the gist:
We all are meant to have a natural curve in our neck (our neck is referred to as our "cervical spine" in xray reports.) This curvature keeps our head balanced nicely over our shoulders, and reduces the strain needed to keep our head up.
Loss or cervical lordosis simply means that your neck is straightening, losing the normal, healthy curve and optimum positioning. The result of this, for me, is that my head often feels heavy and forward-leaning, like a bowling ball in front of my body. This causes increased strain on my neck/shoulders, poor posture, and terrible headaches.
Fortunately, as I understand it from my rheumy, this is not necessarily a permanent condition. I do proper neck exercises and stretches (there are some good ones on this site) to try and better my neck posture, and continue my medicine to combat the inflammation and reduce the muscle spasms. Over time, my lordotic curve will hopefully return to normal -- I certainly have felt much better in that area since starting my NSAIDs/stretching.
Hope this helps.