What Causes Pain In The Tail Bone With A History Of Endometriosis?

I am 32 years old and I was diagnosed with endometriosis 10 years ago and I did get it under control and I did have 2 kids. For the past year now I have horrible tailbone pain starting in the middle of my period and it will even last up to three days after my period is over. Is this related to my endo? and what can I do, should I see my Dr. asap?