You may be trying to do too much too soon. I recently started running also, and did some research on the best way to begin. Everything I've read says to start by walking fast first, then mix in short bursts of running. Begin by walking fast with your arms pumping to get warmed up. Then do some stretches for your legs (lean against a tree and pull one foot up behind you 'till it touches your butt and hold, then do other leg). After you stretch start running until you feel like you can't anymore, then walk until your heart rate recovers, then run again, etc., etc. Do this daily and you will soon be able to shorten your walking time and run longer without all the aches and shortness of breath, as you will have built up your stamina.
Good luck!!