Beds on holiday

Despite my wife buying a hard mattress (Sealy Posturepedic Alexandria Ortho ) to alleviate her back pain it still does not work.However we have been to Barbados and Spain over the last year and she has experienced no back pain from their beds,especially the one that we used for 3 weeks in Barbados.April /May2016.Now we are back home the back pain has returned so it must be the mattress ..Have you any ideas or comments on the difference between commercial holiday beds and normal household beds..Many thanks.Kevin Mulligan.