Nori... My advice try to do alot stretching before & after u'r run.. try performing this stretches on a daily basis (u may need to spend about 10 -15mins) i've been doing this alot and it does help me.. also try applying enough ice on the area where the pain is try. Good luck!!
Okay what I can think of now is to make an appoinment to podiatry. He/She might be able to help and narrow down your problem. But do keep in mind that doing a MRI / X-ray will help you alot and have you tried performing any stretches for your heels.. Can you try this and see if there any pains you feel while doing these stretches ? good luck..
I'm guessing you are starting to have shin splint. Do you feel like a electrifying kind of a pain hitting on your shin when you started running about 10 - 15mins ? also after you finish your run if you massage u'r shin bone using u'r thumb do you feel any pain?
If it's possible try to get a quick MRI check with fisio to find out if it's really shin splint or alternatively most cases you are developing shin splint due to no proper stretches or u'r calf muscles are too tight...
Try to stretch u'r calf muscle before and after your run.. if your are not sure try going to youtube and search for "strecthes for shin splint" and you may find a few good one...continue doing it...applying ICE is a good thing, since you have a race coming soon... you may consider getting this gel called "Fastum" from the drug store and you can apply it.. it's anti-inflam (do check the guide before applying around your shin area before your run) other than that if u are u using old pair of running shoes.. you may wanna check some good one's from asics gel (which i use)..
Are you feeling the pain as below http://orthoinfo.aaos.org/topic.cfm?topic=a00147 2nd or 3rd pix ? Since you say you don't have the pain when you walk barefoot..have you tried changing the shoes? If problem persist after changing a shoe try goin to physio and getting MRI. I hope nothing serious..
I'm sorry to hear you have shin splint...I've been suffering with this pain almost 2 - 3 years and I was diagnose wrongly and was given wrong information. Frustration and not able to watch my weight..it's really painfull not able to run.
TIll I actually made my own research how to get rid of them..basically you could do a few things "Runners Therapist" has given most of the recommendation for you which is good. Alternatively I'm using this gel called "Fastum" try to google it and you shud be able to get it on your drug store.. just apply it mins before your run..you may feel a slight pain but it shud disappear after 10 -15min run.
Most important try to search for various workout to strenghten your Shin by going to Youtube.. or you can also try KT Tape taping method is also seems fine which I've been using now and I've have done 2 half marathon with that.. but always invest in a good pair of running shoe...I'm using Asics gel.
Byw have you tried running barefoot? Does it help? Try all of these and most important try to change the style of running.. landing on forefoot instead of heels..