IMO, everything you've listed are behaviors associated with improper nutrition....He basically is starving for nutrition......
Dogs shouldn't eat the same food for life.....Think about it, would you want to eat the same breakfast cereal every meal, every day, forever? Your dog doesn't want to, either!
By your description, I suspect your feeding a low quality food from a dicount center or grocery store.....You need to throughly evaluate the ingredients in his food.....
Shop at speciality stores or "Mom & Pop" small petfood stores...They will have the better dogfoods for sale...NOT large chain stores!
Start here & evaluate the food your feeding....Then, upgrade to a healthier one....I believe it will solve your problems.....Until then, put some healthy leftovers (From your table) into his bowl along w/his food....No spicey foods, No fatty foods, No sugar, chocolate, etc.
Fresh meats (Cooked or raw), cooked veggies and raw fruits will help him tremendously!
Here's some good resources:
DogfoodAnalysis.com
DogfoodAdvisor.com
DogfoodChat.com
PetfoodRatings.net
DogfoodScoop.com
411-for-dogs.com
Good luck....Let me know if you need more help......Karla
Sorry to hear your dog is having troubles. The food manufacturer may have changed ingredients in his food, or made some other change that is confusing him. Or he may be developing a disorder that's affecting his eating. Either way, I'd urge you to have him checked by a vet. Hope he gets better quickly.