Ance question

So i dont get it often i usually get it a week before my period or when my period should start if i had a regular 28 day cycle. I dont have that my periods are irregular they come when the want and for how ever long they want but i always get maybe 1 or 2 bad breakouts about ever 4 weeks even if im not bleeding and i always have one thats really bad under the skin that hurts. Why is this when my periods are irregular? Of course im thankful i dont have it as bad as others just wondering why this happens?