John in NM
I agree with others that you are making them too tight, but you may get away with it with a different glue. Personally I like hide glue for this kind of work - it is very slippery before it tacks. Try it on a test joint and see if its any better.
I usually glue up the entire drawer box to ensure that its square. If you're having trouble doing that, it sounds to me like you need to make a change to process or glue.