acheyoudaoicibaDictYouDict[ache 词源字典]
ache: [OE] Of the noun ache and the verb ache, the verb came first. In Old English it was acan. From it was formed the noun, æce or ece. For many centuries, the distinction between the two was preserved in their pronunciation: in the verb, the ch was pronounced as it is now, with a /k/ sound, but the noun was pronounced similarly to the letter H, with a /ch/ sound.

It was not until the early 19th century that the noun came regularly to be pronounced the same way as the verb. It is not clear what the ultimate origins of ache are, but related forms do exist in other Germanic languages (Low German āken, for instance, and Middle Dutch akel), and it has been conjectured that there may be some connection with the Old High German exclamation (of pain) ah.
[ache etymology, ache origin, 英语词源]
ache (v.)youdaoicibaDictYouDict
Old English acan "to ache, suffer pain," from Proto-Germanic *akanan, perhaps from a PIE root *ag-es- "fault, guilt," represented also in Sanskrit and Greek, perhaps imitative of groaning. The verb was pronounced "ake," the noun "ache" (as in speak/speech) but while the noun changed pronunciation to conform to the verb, the spelling of both was changed to ache c. 1700 on a false assumption of a Greek origin (specifically Greek akhos "pain, distress," which is rather a distant relation of awe (n.)). Related: Ached; aching.
ache (n.)youdaoicibaDictYouDict
early 15c., æche, from Old English æce, from Proto-Germanic *akiz, from same source as ache (v.).