Cardialgia (9)
I believe the answer is:
heartburn
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cardialgia</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for heartburn that I've seen before include "Disorder" , "Hot sensation in lower chest from indigestion" , "Acidic reflux" , "minor ailment" , "Indigestion of cardiac origin?" .)