Pain in calf from jogging

Have been jogging/walking for many years, 20-30 miles a week. Within the last few months, I have been getting like a cramp in my right calf. The pain lasts for a day or two; I can walk, but can't run for a few days. Then I pick up running again, and within a few days, the cramp (or whatever it is) comes back. I think the calf then looks swollen.
What can be done? The only difference between that leg and the left one is that I have bulging varicose veins on the calf. Long, long time ago, I had an injury; my (hurting) leg was squeeshed in an accident. (Perhaps it was never treated right.)

[RunningMom]

Have you had your running shoes a long time?  Running shoes need to be replaced around 300-400 miles of usage.  The miles add up fast with running long distance.  You also may have an injury from running that would require rest, ice, compression and elevation.  It maybe a good idea to see a sports medicine doctor.