@harleytiger I believe anything is a possible side effect from radiation. While I have dealt with insomnia, I did not correlate it with radiation. Stress and anxiety are more likely culprits for me. Neck fibrosis has been an issue causing nighttime headaches, though. I found that using a topical NSAID like Voltaren on my neck at bedtime, along with some neck stretches helps considerably. Perhaps the stiffness you experience with a prolonged period of not moving your head on a pillow while sleeping is a cause? of awakening. I have read that very high doses of Melatonin can actually cause sleeplessness so I wondered if you have played with that dose? I take 2 mg at most and it really helps me. Chamomile tea at bedtime can be helpful also.