thank ypu for asking this question
well , this lower sternal chest pain
is frequently due to indigestion
only , but we can not take a chance for myocardial infarction
which mainly depends on age (40 yrs and above usually), and some times thin of acute sickle cell crisis if any one having repitative sternal or rib cage
pain (also called vasoocclusive crisis).. and many more reasons ...........