What on earth could be causing my nerve pain in my legs?

I'm not a doctor, of course, but it sounds to me like it could be a disc that protrudes more when you are in certain positions for longer periods of time due to gravity and pressure on the spine. I've had (and currently have) multiple disc herniations, and have suffered similar, worsened nerve pain when in certain positions. You mentioned that your pain is 1000x worse when sitting, laying on your side, or standing for too long. Sitting and standing put a lot of pressure on your spine, so the longer you're doing those things, the worse the pain can get. I have dealt with this as well and in my case, it's often been caused by disc problems. (That doesn't mean that your issue is definitely caused by your discs, but it sure sounds like a good possibility). Now, luckily for me in one way is that my imaging has always clearly shown where the problem was, but not everyone's does.

The other thing, which Doctors should know, is that what affects and/or hurts one person isn't necessarily what affects/hurts another person. Many people have disc herniations/bulges, stenosis, etc..and don't even know it because they suffer no pain or maybe no other symptoms. Others have what appear on imaging to be "minor" issues, but may suffer tremendous pain & symptoms.

Where is your lumbar disc bulge located? I just did a search and it appears that it's possible to have nerve pain in the knee areas due to a T10-11 protrusion, though it's rare. Disc compression or protrusion at L3, L4, and L5 can definitely cause nerve pain in and around the knee area. I know because I've had this myself. If you haven't done so already, do a search for "Dermatome Map." It's a map of spinal nerve roots and can help you to visualize where your nerve pain might be coming from. If you see any correlation to your own situation, then keep looking for another Doctor that is wiling to help you instead of dismissing you. It's your body and you have to live with the pain, so you have to advocate for yourself. Not to be harsh, but I have learned this myself from decades of experience.

Have you seen a neurologist at all or a spine specialist (either neural or ortho)? Or was it your Rheumatologist who said your disc issues were too minor?

@angrynerves Hello and welcome to Connect. I realize that you've been getting the runaround with specialists. Not all spine specialists are equal of course. My suggestion is to see a spine deformity specialist who does a lot of surgical cases for scoliosis. My spine surgeon at Mayo is that type of specialist with both neurosurgery and orthopedic surgery training. When you think about your spinal cord, imagine that it is a rope inside of a garden hose. Every time you bend and move the hose, the rope inside has to slide back and forth to compensate. With scoliosis, you have a few slight kinks in that hose that may have already added some pressure or should I say less mobility to the spinal cord. You described what sounds like a bulging lumbar disc and the protrusion at T10/11. Is that a herniated disc or is that a vertebrae slipping past another one?

I can tell you that when you have compression of the spinal cord or it is touching or raking past some protrusion inside the spinal canal, that can be a confusing problem to diagnose because it isn't clear what specific part of the spinal cord is affected and that can change where contact is made as the spinal cord moves. If the issues are compression at the nerve roots, those are easier to diagnose because those are specific nerves that are mapped in the body and it is all predictable.

I had a confusing case with slight spinal cord compression in my neck and there was no nerve root compression. My pain symptoms moved if I changed my body or neck position, and I had pain felt all over my body which made some surgeons thing it was an inflammatory problem. It was after I found medical literature with cases like mine, that I had an answer. I found that because of reading literature co-authored by a Mayo surgeon and looked up what I didn't understand and that lead me to this medical case in an online journal. I sent that paper with a request for an appointment and I had a C5/C6 fusion at Mayo which fixed the problem. 5 other surgeons missed the correct diagnosis. If you are able to travel and be seen at Mayo, I would recommend my surgeon, Jeremy Fogelson who is a deformity expert on scoliosis. You would need to have insurance that Mayo accepts in order to get an appointment. Here is his information and a video where he talks about his interests. The really good thing about being a patient at Mayo is that all your specialists in different departments will collaborate in your care and discuss your case with each other.
https://www.mayoclinic.org/biographies/fogelson-jeremy-l-m-d/bio-20055624
Dr. Fogelson video
https://medprofvideos.mayoclinic.org/videos/adult-scoliosis-treatment-options-at-mayo-clinic

how about try acupuncture, it helped me