Starting back running after many years (10+) away from the sport. I ran about 2 miles a day for the last 10 days and felt ok(well really I felt like I had never run before but ok all things considered). On Saturday I was about 4 minutes in when I experienced extreme tightness in my calves and had to stop. My calves are still pretty tight today, I tried starting up last year and had similar issue after about a week's running. Any thoughts on what could be causing this? I have stretched after each run so I don't see not stretching as an issue. I never experienced any calf problems when I ran higher mileage (70+) years ago, I can only remember my calves hurting after some very hard work-outs. I am 6'1 185 but with pretty thin legs so I am wondering if my extra weight could be an issue (i was anywhere from 155-165 10+ years ago). Any insight or similar experiences and resolutions would be appreciated.