I had the same problem. Only mine was the side effect of high intensity floor aerobics, when I would spend a lot of time jumping up and down on my tippy toes. I also read an article somewhere that spoke of people who do fast paced step getting bigger calves when they are going so fast that they don't concentrate on placing their feet squarely on the step and let them hang over the edge instead. I am probably guilty of that too. I also used to include weighted calf work in my strength routines.
I got to a point where I felt my calves were going to explode. They were ripped, but just too big and too tight. This article said calves get bigger because of the strenuous moves performed in exercise can actually "shorten"? the muscles. It recommended stopping the offending activity, of course, and to do calf stretching three times a day. I decided for the time being I will not do weighted calf work, I alternate the height of my step so I can concentrate on foot placement. If I want 8 inches, I do a lower impact routine. And I modify floor aerobics so that I am mostly landing on my whole foot or heel-toe. After a couple days there was a noticeable difference.
