Chest Pains when running?

I have been in the army for 6 years.

I have always had issues with running.

Prior MOS was infantry so there were weeks we did nothing but running.

I have always had chest pains. They used to be sharp. They starting being dull and more prevalent especially when my heart rate hits 200.

I already talked to a doctor and had an echo stress test everything came back fine. They did say I have a weak heart for my age.

Due to the unpredictability of my mandatory physical training sessions and not a lot of free time. I can’t do balanced cardio with long distance, run for time, and 30/60 sprints. Along with strength training.

I need to improve my run time.

I am planning on doing 1/2 to 1 mile every day with an elevation mask.

Has anyone dealt with anything similar or have better advice?