I Have Had Pain In The Sternum For About 4

I have had pain in the sternum for about 4 weeks. EKG was normal. I had the stress test, echo cardiogram, lung function about 6 months ago. All were normal. Blood work last week came back okay. Pain sometimes gets better with exercise (and comes back again) or it gets worse with exercise.Pain is on the bone or sometimes just beneath. It hurts when I press on the bone.