There is no "one size fits all" for either endo or PCOS. For many years, I had all of the symptoms of PCOS and then developed much more painful endometriosis.
Without having a laparascopy to diagnose endo, I think a lot of what separates the two is the pain. Endo is more painful for most than PCOS. Have you started on a progestin-related hormonal therapy? Endo shrinks with progestin and grows with estrogen. Combination pills won't help most women with endo but may help with PCOS.
There are hormonal tests that could help you identify if you have "estrogen predominance." Truly, you should see a specialist if your periods are that painful. Pain is NOT normal and you should see a specialist to get a treatment plan that helps you either way.
Not everyone with Endo has the same symptoms. Also PCOS and Endo go hand in hand as well so its possible you could have both/one or the other.