I am experiencing chest tightness (worsened by: worse at night), shortness of breath (time frame: gradually) (worsened by: lying down, exercise or physical activity) (severity: mild) (better by: rest, sitting upright), slow heart rate and heart palpita

Doctor can evaluate. Shortness of breath is not normal, unless it is the mild temporary shortness of breath with sports activities (but even then, one must be sure he is not having more shortness of breath than his sports peers have). Possible reasons for shortness of breath include heart attack, heart arrhythmia, heart failure, fluid around the heart, fluid in the lungs, asthma, a bad case of costochondritis, etc...