Not much they can do for backs (without it costing a fortune) but I can show you some stretches that may help. The only other solution I've found works is a really decent back massage, proper one done by someone who knows what they're doing. Probably cost you about £30, but can have good results if you combine it with rest and the right stretches.

Reckon Johnny S will disagree with you about the fitness stuff - but then do the two of you ever agree about anything? Swear you two are married.