Have you tried medical grade compression socks? I started wearing them when I started getting cramps in my calf muscles during runs and they really helped. They increase the blood flow in the lower leg which helps flush out the area of lactic acid etc. I would reccomend the compression advisory, they also have a medical advisor there who I spoke to at length about my problem and was really helpful.
I got myself a pair of medical grade running compression socks from the compression advisory at around £25 but they are definitely worth the money, much less fatigue in my legs after running and generally fresher the next day. Highly recommended!