Most of your symptoms match those of a bone marrow problem. I'm a caregiver, not a physician, but I think you could be putting yourself in danger by racing, so you should avoid it until you have a medical evaluation.
I don't know how blood and bone marrow issues would be related to your shoulder pain, except that if you have low blood counts then other medical problems are easily aggravated.
Small town doctors are unlikely to have experience with or even know much about aplastic anemia or similar diseases. You can't blame them for that -- these are rare diseases -- but they should know enough to alert you to the seriousness and refer to you to a major medical center with a better chance of diagnosing and treating you. For example, you may need to go to the University of Colorado.
Despite some urgency because of your current set of symptoms, there's one good reason not to panic: you've apparently been living with anemia for quite some time. For you it's been a chronic condition, but I still encourage you to look into it promptly.