I have lumps on the right side of my anus it hurts to sit down and they sometimes itch and I think I'm constipated what could this be?

Hemorrhoids. It appears that you have hemorrhoids and at least one of them is Thrombosed or has a blood clot in it. This is why it hurts so bad. In my office I could take care of this easily and you would not need to go to the ER. It does need to be treated today. I suggest you call your doctors office to see if they can treat this, if not an urgent care or a surgeon prior to the ER.