Why do i often feel very minor discomfort in chest & same area in back,no other symptoms,most days i am perfectly fine & some days i feel it,going on very long time,could this be heart problem, could it go on for years without changes? anxiety?

My hunch is you are using muscles you have not used in a while and they are hurting. Your body is talking to you. Listen and take good notes such as what you were donig, eatng, drinking the day(s) before aching started again. If your BP, lipids, BMI and family history for early heart disease and have never smoked not likely heart issue. After you have a good diary it may be clear to you.

These symptoms may be rib cage musculoskeletal in origin, possibly from tension. In cases like yours, for peace of mind about your heart, I recommend a cardiovascular checkup including EKG and a treadmill stress test. Your primary care MD can examine you and arrange the testing.