I have had insomnia since I was 10. I did not start taking medication for it until about 10 years ago, when I was at my doctors and he walked in and asked when was the last time I slept. With medication I can get five to six hours of sleep. Without medication, three hours to four broken hours is about the max. Eventually, you get more for a day or two because of sheer exhaustion.
It runs in the family. Must be another one of those genetic quirks.
I have tried all the suggested remedies--warm milk, read a book, listen to soft music, listen to waves hitting the beach, counting sheep, etc. Anything that requires or results in the stimulation of the brain will keep me awake. I went to a sleep clinic once and the diagnosis was psychophisological insomnia, which meant it was either mental or physical. That is one of those diagnosis that covers the waterfront pretty well.