Probably has the wrong shoes and is running too much. I weigh 195-200 pounds and cannot run more than every other to every third day. I run between 7-8 miles each time. It is a lot of stress because of my large frame so I allow ample time to heal and make sure that the shoes I am wearing are not worn out (past 250 miles or over 4 months old) and that they are the correct shoes for my foot type. Also, I exercise (between runs) cardiovascularly on machines. I also lift weights and eat somewhat well. I find juices and fruits give me an extra boost of long sustaining energy.
Hm - a LOT of similarities. I weigh about 185 and try to jog three times a week (Mon, Thu, Sat). But I only run 25 minutes or so, about a third of that running up and down a pretty steep hill a few blocks from my house. So I would imagine that it is equivalent to running about three miles or so. I exercise (moderate weights, calesthentics) right before I run. I think this helps to stretch out the muscles, warm them up, and thus preclude injury.