You are describing exactly the problem I've had. I would run, strain a calf, rest/recover -- and then run and strain my calf. All since I turned 44 -- very frustrating.
Have solved it by stretching -- but stretching the whole leg, not just the calf. Start with the calf, then the hamstring, then the gluteus. In the mornign before I run and then in the evening before I turn in.
At least for me, it really works -- when I'm disciplined and keep up with it I don't have a problem anymore.
That is a good point. One thing that we often forget is that all of the body parts are connected, so that is why a problem in the calf might be alleviated by stretching the back, for example.
“He is happy whose circumstances suit his temper but he is more excellent who can suit his temper to any circumstances” David Hume