new cage, fighting,please advise

[potfiction]

hi guys.i have two dwarf hamsters from the same litter.i got them 4 days ago.today i got them new big 3 story cage,cause the other was small.to move all their stuff i put them in their balls for bout 12 mins while moving all their stuff.after putting them one by one into the new cage they were very agressive towards eachother and had a few fights.but has calmed down a little now.the one also ran alot on his wheel and then he just sat in one of the pipes very still for long.he then again runs and sit.is this normal,do i need to do something.
it seems that the fighting has gone away a bit.they just squuek when they pass eachother in a pipe now,or if they run into eachother.is that normal.one does not run to the other with the purpose to fight it seems,also how do u tell the dfference between play and real fighting.is it normal for one of them to build the nest?i know its lots of questions.thanks again
please help asap.