Dull persistent pain (4)
I believe the answer is:
ache
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dull persistent pain</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ache that I've seen before include "Hurt; yearn" , "Pine" , "Suffer dull pain" , "Persistent dull pain" , "Throb - hurt" .)