I feel embarrassed about this, but I struggled for quite some time with my floor pump (Specialized Air Tool) and the tires on my new bike. Every time I tried to pump them up, it seemed like there was a lot of resistance from the pump. After reading through the posts in this thread and others, I realized that there's a "sweet spot" when attaching the pump to the valve. If it's not on tight enough, the valve doesn't release and allow air in. Of course that's what was causing the resistance!

It does help to release a little air before connecting the pump to the valve and it also takes a little fiddling to get the pump seated properly so that the valve releases.

Nice to know that others have had the same issues and that I'm not alone!