Please, please: see another doctor. Keep seeing doctors, alternative healthcare practitioners, psychs and nutritionists until you find a way to heal. You know you aren't well. Stand up for your yourself - you deserve to be healed. You don't deserve a life of pain. So, don't give up.
My father complained for over five years of pain in his shoulder and neck. His doctor kept telling him there was nothing wrong. By the time cancer (originating in the nerve bundles where the neck meets the shoulder) was diagnosed, it had spread through the body, leaving him very little time.
Remind yourself of what it felt like to be healthy. Don't have fear, have strength! When you start to despair, come back here and reread the messages of support.