Back pain (low back) & endometriosis ? How does that work?

Charity • ❤️Three Angels & One Grand Daughter❤️
I have had low back pain for some time. I was involved in a few bad car accidents since child hood and only with in the last few years it's worse.  It seems around my cycle or before hand it gets real bad. Too the point I want to cry and have to stretch it out. I didn't think the two were linked. How is that? TIA