Read the dictionary definition of ache. All definitions for this word.
1. a dull persistent (usually moderately intense) pain
2. have a desire for something or someone who is not present
1. She ached for a cigarette
2. I am pining for my lover
3. feel physical pain
1. Were you hurting after the accident?
4. be the source of pain
See also: Merriam-Webster definition of ache