Left leg starts hurting mid-run.?

Every time I get on my olyptical exercise machine this happens. I'll start out strong, everything will be fine for 2 minutes. Around 3:30 seconds into my run the left side of my calve muscle becomes so tight that it hurts to continue. It is not my stamina limiting my run times, it is just my left leg. I weigh 187-192 lbs and am 5' 11" body fat around 10%