Yea if your cases have grown past their max length it could cause a problem but I think that it would be binding the bullet up first and cause a serious pressure spike , measure you fired cases and see.
Your "head space" is a mechinacal factor that shoulden't ever change after the barrel is tightened so I don't think that head space stretch is possible or at least I've never heard of it.
Now the question for you to help solve your problem.
1) what type gun and what caliber are you
shooting?
2) what type of ammo are you shooting if
reloads state your load and how many times
the brass hase been fired and what type of
resizing your doing.
3) is the gun new and this has always been a
problem or is it something that just
started , if it just started did it start
all at once or has it slowly increased?