Ok. I haven't been exercising for 3years. I just started out last week. When i'm jogging on a 400m track, my calves tighthen (feel tired) after jogging for 300m. My target distance is 2.4km.

Can i know what are the possible causes for this problem?
Does not warming up the calves contribute to this problem?
Will jogging more help solve this problem?

I do feel alittle breathless when jogging but this problem gets better when i breath in more air.

*sorry for my bad English.