When you've been out shopping with your good wife/ladyfriend/hetero life partner/etc and spent the hours acting as a pack mule. And general shopping trolley. The back and general lumbar region may begin to ache or throb. This phenomenon is known as 'shoppers back'
Sinead: Thank you so much for carry my bags sweet heart.
Paulina: No problem, but i think i may need to stop for some whippy soon as i feel a chronic case of shoppers back coming on.