Merriam-Webster's Collegiate® Dictionary, 11th Edition
ACHE
I. intransitive verb (ached; aching)
Etymology: Middle English aken, from Old English acan Date: before 12th century
1. to suffer a usually dull persistent pain , to become distressed or disturbed (as with anxiety or regret) , to feel compassion , to experience a painful eagerness or yearning ,
II. noun Date: before 12th century a usually dull persistent pain, a condition marked by aching