Could I have Endometriosis? I have extremely bad cramps on my period and my period are really heavy and last long. I got put on birth control and my periods are regular. The cramps still are bad and my periods are still heavy. (I'm on my 3rd month of birth control pill, ortho tri cyclin)

I'm not sure what all the symptoms are of endometriosis. I am a virgin so I don't know if I will have pain during sex. Could someone please explain?