I can't run properly because I have a massive blister on my right foot. It's located just under the left side of the arch of my right foot. It seems strange that I haven't got one on my left foot. I don't know whether it's the footwear I'm running in or the way I'm running, or maybe I have one leg longer than the other and I 'm putting more pressure on the right foot. I have fairly standard running shoes but I'm not very technical so I wouldn't know what type they are. Can anyone offer an explanation for why I'm getting blisters or what I should be doing to prevent them please?