Shoes just started to rub, advice wanted

Hi,

 I've been running now for all of three weeks. I bought a pair of running shows halfway though week one. They're New Balance something (sorry, typing this at work so don't have them to hand). I bought them from a decent shop and tried a load of pairs first, running up and down outside along with other punters.

 They've been fine for the for the first 7 or so runs, prob 20-25 miles, until yesterday I started to get rubbing on the insides of the sides of my heels on both feet. Not much, but definitely noticable and I reckon it would cause a problem after a while.

I don't think I can take them back now, but are there any tips on how to fix this, or alleviate the problem? it definitely hasn't happened before, so I could almost convince myself I put them on wrong!

 Thanks

A smear of vaseline on the affected part of your heel might help to stop the friction.

Strange that they havent rubbed before so hopefully a one off

good luck

Thanks cougie and susiebe1.

Same socks, or at least same type - straight out of the packet. Weather was possibly warmer than other runs, but it was <8am so not tropical.

 I'll give the vaseline a go. We still have some knocking about from when my son was a baby (that's why we have it - honest!).

 I'll see what happens next time, and try to work out if anything has changed.