Should i be concerned with chest pain underneath breast and on side of breast..if my ekgs..echo..stress test and blood work are normal..doesn't last?

Needs exploration: Any persistent symptom needs evaluation. It sounds as if you had a very thorough evaluation, and that it isn't a heart related cause. Other possibilities such as a gastrointestinal or musculoskeletal cause should be explored. Work with your providers. Good luck.

chest pain: If you are a 28 year female and having pain under breast ( I am not sure if it is left or right, first thing to do is a complete physical exam by a physician. Pain could be coming from breast rather then the heart or even a rib or sternum.

Breast exam: Please go visit your obgyn for a good breast exam -- you probably have fibrocystic breasts.