I think you can try the B12 oral tablets. A reading in the 800's is okay. But you don't know at this time if you are coming down, or stable at it.

I have a B12 thread in the stickies now at PN board. Please read that:
http://neurotalk.psychcentral.com/thread85103.html

New studies show oral works just as well as injectable.
Most of us get our B12 online and use the active form methylcobalamin.

I'd try taking D3 4000 to 5000IU daily. This is what they are doing in Australia today:
http://neurotalk.psychcentral.com/thread81900.html
Lara put that video up, and it is very interesting and helpful.

The Vit D info is pretty new. All the doctors are getting CME on it, and still there is confusion about D2 vs D3.

This link has most of the info on it...and there is alot.
http://www.vitamindcouncil.org/

RSD has associated with it, a calcium metabolic problem.
You know the papers I've found about treating early RSD that have calcium channel antagonists as treatments reflect the
actions of calcium that are abnormal during RSD. I have not been able to figure out how this calcium thing is related to RSD to the extent that I am comfortable with the very high dose Vit D
research. But since your own doctor advises raising it for you, I'd go ahead with the D3. Just keep an eye on your pain levels etc while doing it.

The testosterone effects...are you on opiates? This effect is pretty much standard for males on high dose long term opiate treatments for chronic pain. It has to do with opiates/receptors in the pituitary/hypothalmus area. Those testosterone injections have to be painful. They are depot shots.
Testosterone works in males to keep bones strong (like estrogen for females). Also important for muscle mass maintenance, and strength. Sexual functioning is obvious.
If you don't want the shots, I'd still use the topical gel forms to keep it at some level, even if you can't get optimum levels with it. This will protect your spine, and hips etc from osteoporosis.

Do the best you can at this point. The new studies are NEW, and suggestive. I myself am using 4000IU of D3 daily, during the winter, and not during the summer. I have found it to be useful for myself. You can maintain B12 with oral tablets, and they don't cost much.
So far looks like you are doing an adequate job of it.