Hello Ashleycat:
As for straining, I would say that if the poop is formed then there is nothing to worry about. My cat Max makes a face too.

My other cat Speckles will scoot as well and yes, those nasty brown streaks on the carpet are annoying. Specks is 17 and a bit **ahem** fluffy so she has a problem cleaning back there. I help her when I can but I work all day so sometimes I come home to a surprise. I don't know what to suggest to stop the scooting. First, make sure she doesn't not have worms or anything similar that irritates the bum.