Shoulder pain on pocket sprung memory foam mattress.

Hi Marcus, 
 
Thanks for your question. 
 
It does very much seem like your current mattress is completely wrong for you if it's causing those pains. 
 
At your body weights we would match you with a Medium and Firm split tension to get the correct level of support each;
 

 
Side sleepers in general should be avoiding anything too firm in the top layers as this will definitely cause those pains. We would need to know your wifes sleeping habits in order to definitively recommend a product. 
 
With that in mind have a look at our Artisan Naturals or Artisan Luxury. 
 
The Naturals is a good true medium in it's upholstery providing a slight sink but not too much. The Luxury is the softest mattress that we retail giving that luxurious sink into the top layers. If your wife is a front sleeper we wouldn't recommend the Luxury as too much sink can cause an unnatural arch in your back. 
 

 
I hope this helps but if you have any further queries please don't hesitate to contact our office on 0161 437 4419.
 
Kind Regards, Lee.