From Longman Dictionary of Contemporary Englishbackacheback‧ache /ˈbækeɪk/ noun [countable, uncountable] MIa pain in your back
Examples from the Corpus
backache• Liz Hurst knows all about backache already.• After a few days I started to develop backache in the lumbar region so acute that I could hardly move.• But it has its mundane side, like backache and swollen ankles.• No morning sickness, no backache, no obscure cravings.• As my father remembers the story, the backache soon took a bad turn.• After a month or two the backache had eased, leaving me with sciatica.• Infection in these nodes may lead to backache.• Unfortunately, this is not the case with many millions of people whose backache is worse after even a short drive. 