The Collaborative International Dictionary of English v.0.48:

Ache \Ache\, v. i. [imp. & p. p. Ached; p. pr. & vb. n.
   Aching.] [OE. aken, AS. acan, both strong verbs, AS. acan,
   imp. [=o]c, p. p. acen, to ache; perh. orig. to drive, and
   akin to agent.]
   To suffer pain; to have, or be in, pain, or in continued
   pain; to be distressed. "My old bones ache." --Shak.
   [1913 Webster]

         The sins that in your conscience ache.   --Keble.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Aching \Ach"ing\, a.
   That aches; continuously painful. See Ache. --
   Ach"ing*ly, adv.
   [1913 Webster]

         The aching heart, the aching head.       --Longfellow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

aching
    adj 1: causing a dull and steady pain; "my aching head"; "her
           old achy joints" [syn: aching, achy]
    n 1: a dull persistent (usually moderately intense) pain [syn:
         ache, aching]

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "aching":
   Heimweh, ache, achy, afflictive, algetic, angina, backache,
   bellyache, blow, cephalalgia, chilblains, chill, chilliness,
   chilling, cold creeps, cold shivers, colic, collywobbles, cramp,
   creeps, cryopathy, cut, desiderium, distress, dithers, dolor,
   duck bumps, earache, fret, frostbite, gnawing, goose bumps,
   goose pimples, gooseflesh, grief, gripe, gripes, gut-ache,
   hankering, headache, heartburn, hemicrania, homesickness, honing,
   horripilation, hurt, hurtful, hurting, injury, kibe, languishing,
   languishment, lesion, longing, mal du pays, maladie du pays,
   megrim, migraine, nasty blow, nostalgia, nostomania, odontalgia,
   otalgia, pain, pang, passion, pining, pyrosis, shivering, shivers,
   shock, sick headache, sore, sore spot, spasm, splitting headache,
   stomachache, stress, stress of life, stroke, suffering,
   tender spot, throbbing pain, throes, toothache, wound, wrench,
   yearning, yen