The word ache can combine with different parts of the body to form compound words. However, the list of words is limited. The adjective sore combines with many more.
Compound words with ache include backache, bellyache, earache, headache, heartache, stomachache and toothache. The word bellyache is an informal word for stomachache. In contrast to the other words, heartache does not describe physical pain but emotional.
For most parts of the body, the adjective sore is used. Examples include sore foot, sore knee and sore shoulder. However, the word ache is used for a few parts of the body. It derives from Old English.
