Well the endometriosis explains it all for me! I too have the same thing! It is VERY painful! P.S. I've given birth 5 times and it is very comparible to that, just excrutiating! As soon as my youngest gets old enough I plan on a hysterectomy. I do hope you can get some relief soon.
What a blessing you are to have been through so much at your young age. A cancer survivor and all.