Hi Nelly King, 
 
Thanks for your question, 
 
We have a detailed article on mattresses and how they can affect neck pains here
 
We have a wide range of tailored and tested mattresses that cater to chronic neck pain sufferers. Our Artisan Naturals mattress in medium spring tension and Origins 1500 mattress are particularly popular for those seeking to sleep soundly and wake up refreshed, without that constant pain.
 

 
Although I would also take into consideration that you are currently using a Sealy Posturepedic and if this has affected your sleep for the better you may want to stay with a firmer comfort layer as this is what your body is used to. 
 
I hope this helps if you have any further questions please don't hesitate to contact the office.