Did they check your thyroid levels and your blood glucose?
You are not alone. I myself had a sleep problem which has ceased - i was literally bumping into people at the store getting sleep aids so your not alone. My nights were spent up intil morning. Unfortunatly, i think that something in your life is bothering you. My suggestion to you which I wish I would had done sooner - is to get help for it. Dont drink caffeine - and I hope that you get back on track.
How long have you been feeling like this? Have you been tested for anything? If its been a while, you may want to look into Chronic Fatigue Syndrome (CFS or CFIDS), This is a long shot too, but look up Hugh's syndrome (sometimes refered to sticky blood syndrome): http://www.hughes-syndrome.org/index.htm
You're not drinking/eating any artificial sweeteners like Aspartame or Succrolose/Splenda are you? They cause a number of health problems including chest pains and fatigue.
Lack of sleep can make things worse too, have you tried sleeping aides, even a natural one like Meletonin?