I got a pull in my calf doing step a FEW times. I had to rest it from step for 4 weeks, and got some wonderful advice here for stretches. This is the advice that was given to me, and it worked wonders. BUT. you really have to rest for 3-4 weeks for it to heal. As in not doing cardio that will aggravate it (as Step or running would do).
Here are the stretches that worked:
The BEST stretch I've found is to stand on a stair like you were going to be doing calf raises (or 6" high step platform works great too ). Hold on to something for balance. Lower your foot like you were going to begin a calf raise, but just lower it down slowly until you really feel a stretch in the calf/ tendon. Then use your other leg to push yourself back up. (do NOT do a calf raise to push yourself back up) Do 2 sets of 10 (slowly) three to four times a day. Then, as it gets easier and you need more of a stretch, the PT said to add weights to it (ankle weights, a weighted vest, or she also said you could add weights to a backpack) to help deepen the stretch. Then, as it continues to improve, she said to continue the stretching but to do the sets faster, more like you are pushing off for running .
Personally, I wouldn't go to a doctor unless it doesn't improve with rest and stretches.