I been having pain in the middle of my chest that last for few seconds and then go away. it's been going on for about three days should i be concerned?

Pain that only lasts for a few seconds is rarely indicative of something serious with your heart or lungs. Don't be concerned.

While the description for the pain makes it less likely to be due to cardiac ischemia, the possibility of important organs being involved in different other ways makes it important to seek medical attention. Majority of times pain is found to be musculoskeletal otherwise, work up likely needed.