What can cause extreme fatigue, muscle aches, daily headaches, rapid weight loss, and neck stiffness for over 6 months?

I hope you understand that you're not alone. I've had the same symptoms since dec 15th, 2008. I woke up that day with the worst body paid I've ever had in my life. I was curled up in a ball crying and couldn't get out of bed. It feels like you're going to die and wish you would! I've had colonoscopies, iodine xrays, 130 blood tests and every other test you can think of.  My doctor thinks I have Inflamitory Bowel Disease but it's still a mystery. I've lost 60 pounds since this started and am now below my min weight for my height of 6'3. I've been tested for everything from the common cold to aids and NOTHING. It's not in my head or yours. I know what the doctors think and say about it being in your head. There is nothing worse than being sent to a pain management doctor in mesa arizona and have him profile you as a drug addict or dealer. They assume you are just trying to get the meds. Guess what, we don't want pain killers! We want a cure!  Here's what I would do in your case. Start from the begining and think back as to what you did before this happened. Did you eat raw fish or meat? You might have an unseen tape worm.  I would also be tested for h.i.v or hepititus. Also go to a G.I. doctor and get a colonoscopy done. You arent mentioning any abdominal pain but you might have forgotten to mention it with the extreme body pain you're having.  I also went from being an avoid hunter, fisherman, Motocross Racer(20 years) to not being able to get out of bed or function from the body pain. I know what you're feeling so don't think it's just you. There are tens of thousands of people with this same issue that can't be explained but keep your head up. From everyone that I've spoken with that has all gone through this say the same thing. It lasts a year to two years then one day you wake up and it's gone. You start gaining your weight back and never have this issue again if it's not anything I listed above. Best of luck and do yourself a favor, get 10-325 percocet and 10mg oxycontin. Don't take my advise on that, ask your doctor. I weigh more than you and i'm on 30mg oxycontin so it's based on what you can take. It will help you function a fairly normal life. .