Severe low back pain. Couldn't find out.

I don't if my severe lower backpain is because of my pelvic problem or my severe backpain radiates to pelvic , my all local docters said im good , but I have constant dull ache in my pelvic from 5 months and severe low backpain , my backpain increase when I work , house chores , or sitting for too long or standing for too long , backpain is contant from 4 months , sharp pain in my lower back , had xray and ultrosound and mri , nothing comes but only endometriotic cyst and minimum fluid in pod after severe pid  infection had no. Of treatment with local docters also took no. Of medicines from allopathy,  homeopathy and ayurveda nothing is working. And my feet also vibrates . What it could be when my nearest docter couldn't find out.