Very well put by Tangle!
Broadly speaking unless blood is being drawn and they are in a full out fight, then you need to let them get on with it. It is normal dominance behaviour.
If blood is drawn and one pig is visibly being hurt, then they need to be separated and once that has happened and blood is drawn, then they will most likely never be able to be put back together.
how big is their cage? A pair of males need more space than the average pair of females. If their cage is not big enough for them to be able to get well away from each other, then it can contribute to arguments. As the guides linked above say, having two of every item helps. Having open ended hidey houses so that one pig doesn’t get cornered can also help.
I have two young males myself and even though their original cage set up was at a recommended size, it was clear that they would benefit from even more room. Pretty much as soon as I made their cage bigger, I noticed that their dominance displays and little arguments settled right down. May have been coincidence but they don’t often bicker now.