pain while running near subclavian artery
I just recently started a regular exercise program that includes running and light weight training.
Now that my running pace is improving I am having a weird problem at around the first mile to mile and half of most of my runs. If I push myself at all at the start of the run then there will be a sudden, sharp pain under my collar bone (either side but usually left) about an inch and a half away from where the collar bone meets the sternum. When it hits I can feel a sharp pain that pulses with my heart. It feels like there's a build up of pressure there in the vein/artery.
Slowing down and swinging the arm on the affected side makes it go away after a few seconds and it rarely returns during the run.
Prior to starting the new program I occasionally hiked or biked, but no more than a couple times a month and only ever casually.
I'm 32, 6'1", 185, have a resting heart rate in the 60s and have always had a low blood pressure (100-120 / 60-70) when not regularly exercising and much lower when on a regular exercise program.
Any thoughts on what this might be?
Is this something that I should worry about?
Are there exercises I can do to alleviate the problem?
How might I avoid this becoming more serious?
Thanks for the help.