I recently got refit on my bike, with some significant, more aggressive, changes in position (more forward, lower).

I had no problem during practice, and had a reasonably comfortable CA 70.3 on the bike leg. However during the run I felt like I couldn't take a deep breath, and that I did the whole run breathing fairly shallowly. The run wasn't horrible, but it was about 10 minutes off my expectation. I don't remember having any trouble breathing on the bike, and I have absolutely no history of any kind of breathing issue.

I'm guessing the breathing could be related to my bike position. Is it common? If so, does the problem alleviate with more training time in the position?

Thanks for any advice,
Greg