Look into multiple sclerosis or myasthenia gravis as possibilities. Try a different neurologist maybe at Mayo or a university hospital where they see more unusual cases. Note that my son and I both have a rare hereditary neuropathy that has caused ongoing weird issues like that for decades. Very slowly progressive. I was tested for suspected ALS, MS, MG and my son for CMT but we have extreme cases of HNPP. It’s very frustrating and challenging, impacts quality of life yet doesn’t stop us from living life. It will probably not shorten our lives. I share this to give you hope that it may not be anything life threatening. Lots of weird and unexplained neurological problems out there. Look for a neurologist who will at least listen to all your concerns. Prayers for you.

Hello, i was reading what you wrote, and i find that i have almost the same pain as you, 3 weeks ago i had xray done and the results were not that good, it says that i have (minimal sclerosis at the inferior aspect of the left sacroiliac joint unchanged) i had xray done before no one ever told me, i have the same pain as you, of the left side knee , back, and up the butt and even a little upper, also now i can feel pain on the right side knee, the pain that i get if i sit down for one hour or more and get up that is really when i have the pain, if i walk goes away. I take tylenol it halps me a little, i don't know what to do, i hope you feel better, take care