MasterGunner - I have chronic back pain, dengenerative disc disease, have had dozens of acute episodes where I couldn't walk and missed work (all lower back, but upper is starting) and gave up all kinds of activities along the way. I have done a ton of research. I'm not a medical pro, but I decided after 15 years to take control of my own course. I hope I can help.
First of all, you will be able to fix this and get off pain killers. Ideally you can do that without surgery. It will take some more research, and some good people who can diagnose and treat you, and probably some hard work on your part to exercise and strengthen. Don't try to figure that out yourself....you can do more harm doing the wrong thing.
Generally, if you have a problem that they can clearly pinpoint and attribute symptoms too, and those symptoms are severe, you could be a candidate for surgery. For example, if they can see and tell for sure that a ruptured disc is pinching a nerve and you have all the symptoms associated with that in the right places, that's what they look for.
The fact that it comes and goes means that you could just be irritating it, and perhaps physical therapy (which can include manipulating and strengthening) can help. I'd recommend that over the quick fix of the chiro. Also, people walk around all the time with bulging/ruptured discs and no symptoms. Consider yourself lucky when it "goes".
With the injections, they were trying to isolate the problem. If you have pain and they treat an area, and it helps, that's good. If you have no pain at the time, it's hard to conclude anything. It's not fishy, just a diagnostic process.
You may have done these things, but here's what I'd do. Insist that your primary refer you for an MRI and a neurosurgeon consult. Also, you can definitely benefit from PT. You might want to do that in parallel, but the right place will be very cautious and gradual, and can give relief, expecially with the right strengthening exercises. If it's extreme and surgery is needed the nuero will figure that out.
If they can't conclude anything, get a second opinion. Your current situation sucks, but is a good chance to get into that diagnostic process....go for it.
I hope you have a situation where you can fit in the appointment and deal with all this.
In my case, nuro said I was not a surgery candidate. I understand why, even though I wish there was a quick fix. It was a combo of not having dramatic symptoms (had sciatica, and tons of pain, but basically not peeing in my pants) and having degenerative discs up and down, so long term, I'd just be chasing the problem and fusion etc might cause a chain of problems.
I ended up with a physiatrist, who looked at the MRI found arthritis and extreme inflamation in the facet joints, and I started with relatively safe steroid injections in those joints today. Painful, but you're a vet...I'm sure you can handle it! 15 years ago I went through similar process and had epidural injection of steroid. Look it up you'll see the difference. The latter was to calm the disc down which was irritating the nerve and causing horrible sciatica. The first worked great. Hoping for the same this week.
If that works my plan is to get back to at least walking 15 miles/week and doing the core exercises from PT. IF I can play soccer with my kids I'll be happy...if I can backpack and camp, I'll be ecstatic. We'll see on step at a time.
Good luck! I'll check back. It was nice to find a recent post where maybe this can help. I was just looking for something related to what I had done today.