1) Ache 2) Aching 3) An ache localized in the back 1) Knottyspine 2) Lumbago 3) Pain 
Non-specific term used to describe back pain; generally refers to pain below the cervical level. ... (05 Mar 2000) ... 
(bak´āk″) any pain in the back, usually in the lumbar or cervical region, ranging from dull and continuous to sharp and throbbing.
Type: Term Pronunciation: bak′āk Definitions: 1. Nonspecific term used to describe back pain; generally refers to pain below the cervical level.
Pain that can be felt anywhere on the back. Backache can be a common symptom during pregnancy.
[n] - an ache localized in the back
noun an ache localized in the back