Shin splints are the #1 most common running injury. I used to have serious problems with them when I was a college undergraduate, but now I have gotten to the point where they only occasionally show up as mild discomfort. Shin splints are from pounding the ground too hard. The only way to get rid of them is to change your running form. Certain shoes can assist with that but generally it is up to the runner to concentrate on landing softer and more towards the mid-foot instead of the heel. Shortening/quickening your stride can help. Picking shoes is both difficult and important. Running stores can give mixed advice, try to seek out different opinions. It is up to you to pay attention to your running form and then find a shoe that matches it so that you have the least possible impact on your legs. There are shoes out there now that will force you off your heels (Newtons) but if you are not very careful you will end up with other injuries. Generally, just look for something light weight without a thick heel. My shin splints were the worst when I had shoes with thick heel padding--it doesn't help. Even if you get the shoes and form right, they can still show up (probably because of the hard pavement, like you mentioned). Warming up before running can help--not just stretching but something to get your heart pumping for awhile. Also, do some strength training, focusing on the calf muscle. Another thought I have is that maybe your shin splints progressed into a stress fracture. It takes about 2 months for a stress fracture to heal, so if you took a few weeks off running it won't make a difference. For that reason, I would recommend seeing an orthopedic doctor. Hope that helps, good luck fighting off the injuries.