It's possible that the cleats need to be adjusted. A slight tweak to cleat positioning can make a HUGE difference in foot comfort (or pain if you go the wrong way!). If your shop has a trained fit person on staff they can likely help you out with making sure the cleats are at least close.

But yes, also possible that it's tension to some extent. I try to make a conscious effort to wiggle my toes every so often and that helps me (but my problem tends to be numbness down the outside of my foot).