Symptoms of wrong-sized shoes?

Hey all,

Okay, I said in a different post that I have plantar fasciitis. It doesn't bother me very much if I take the time to stretch appropriately and really warm up. But, today I ran into a new issue. Well, I say that - I've hit this before, but it actually lasted a while today - to the point where I cut my run short.

Here's the deal - I have low arches (flat feet, whatever) and I own a pair of nike + running shoes. I may have gotten a little excited about finding them on sale and bought the wrong size. Anyway, here's what I encountered today, and have had hints of in since I got the shoes. I warmed up on the bike, interval training on the fly - I moved from bike to treadmill, planning to knock out about 3 miles. Well, my pace sucked because I wasn't used to transitioning, but when I got to about 3/4 of a mile, I started noticing that I had to kind of stomp my heel while I ran - you know, the thing you do when you try on new shoes and want to seat your heel in place to make sure they fit right? Well, every...20 or 25 seconds, I'd have to do that - but only on the right foot. Then, I started realizing I had a pain in my foot. The location was on the underside of my pinkie toe just before foot connects to toe, a real bony area of the outside of the foot. Last, I started getting a pain that felt like I was rubbing a blister behind the ball of my foot, right in line with my big toe, but closer to my heel than my toe.

I immediately thought I had shoes that were too big, but it only happened on the right side. And for reference, I re-tied my shoes before I started running. Has anyone had a problem like this? DO I have the wrong shoes, socks, is my gait screwy? Any help or direction is appreciated.

-R.