SI joint pain crippling

Struggled with this for 15 years now since I was 21. It started as what the doctor called a pulled muscle at the tail bone area. The pain was so extreme I could not bend or even sit up out of bed. The pain was beyond 10 as I could barely think with it. So I avoided it and rested. After 3 months of being bed ridden I eventually got moving again. No problem. Then once a year every year I would pull the muscle again from just any bending motion and again, 3 months in bed. This continued until I was 24 and after pulling it I was given a back support. Then just like magic no pain with movement. I was delighted. However about a month after this, only removing the back support to sleep, I had removed it and pulled something. But this time my disc bulged as well. Sadly the pain is completly isolated to my Si joint so as im not a typical case with syatica, Im told theres no treatment and nothing can be done disc wise. I would eventually require a raised chair to sit as im 6'5 so my hips are a 90 degree angle. Anything lower or withoit support il be in pain shortly after. If I dont use an ortopedic matress, my back will slowly go into spasm with any other type. Iv worked out, lost weight, built muscle, been to physios, no help. Im in no shape now at all but still hav the weight off. And muscles were not good core so maybe thats not a dead end or i wasnt hitting the ryt ones. Eventually found a chiro who took the constant nerve pain away. Prob is im still dibilated with the joint and back easily hurting. Tail area and then it travels up. Wat i think is the nerve is just si joint. Anyway I recrntly discovered my originally doc was trash and then I met 2 consultants who straight up didnt do their job. So it drew out this process. Mostly self discovery. Only occured to me now that maybe reddit is an idea to ask as its a unique case. Mb thers a muscle responsible i need to hit that will give me my life back. Who knows. Sorry if words r stuff is bad pain returned tonyt so here i am. Any ideas or questions welcome