Chronic tooth pain following cavity filling

Thank you to anyone who reads this.
About three and a half years ago I visited a dentist for a routine checkup. They said I needed to get some old cavities refilled and I had some new ones.
So I got my cavities filled. One side went okay. The other side, not so much. My two last teeth on the upper right side got refilled, and then I was in pain. I wasn’t in pain before the dentist, just after these being filled. This led to a root canal on both teeth. The dentist insisted on not placing the permanent crowns until the pain had subsided (spoiler: it didn’t). So about two months later they decide they have to place the permanent crowns.
The pain never left. I haven’t eaten on the left side of my mouth since those procedures. I still have terrible hot/sensitivity. I have pain if I chew there, I have pain if I do nothing.
I have gotten the crowns placed for a second time. I have had the crowns filed probably 5-6 times (not a joke). I have seen countless other dentists, endodontists, specialists, a maxillofacial surgeon…ect who all say that the root canals are “done beautifully” and they have no idea what is wrong with me.
I can’t afford to keep going to specialists because they each want their own set of X-rays which cost hundreds of dollars and I have already spent thousands.
I just want to know…has anyone ever seen this happen? My other teeth hurts sometimes too now. I’m terrified of having any more work done.
I went one endodontist about two months ago that said I may have a hairline fracture that resulted from them placing the rod in my tooth for crown placement, but I had this pain before the root canal so I am unsure about that.
Is there any advice anyone could give me? It feels like this has taken over my life. Could this be mouth cancer? Last time I spoke to my GP my insurance refused to cover it so that is not really a route I can go.
Anyways, sorry this is so long. If you are reading this still…thank you.