Endometriosis

Hi, I recently came across a video talking about this and I couldn’t full understand and I just wanted to ask maybe someone can explain it to me.

Honestly ever since I can remember I had very bad period cramps and it usually only last the first two days or sometime just day one and I would take a lot of pain killers but recently the pain has gone down so much I barely take pain killer maybe 1-3 pain killers

And I also did an ultra sound when I was younger and eveything seem fine.

Plus I always have a regular period no issue sometime late due to stress or weight gain

But hearing about this Endometriosis and I am even more curious how do you have it?

Thank you for taking your time to read this.