Hi stevenkabc,
It’s very possible yes and you could be sleeping in a “hunched” position. It’s also possible that it could be a pillow issue.
I’m not sure how long you have been sleeping on the mattress or whether it was working for you initially and then you started developing your “symptoms” or whether they were there from the beginning but it’s also possible that this is part of the initial breakin and adjustment period for any new mattress or that your choice was “right on the edge” of being too soft for your body type and sleeping positions and the lower quality foams in the comfort layers may have softened enough to put you over the edge.
If you do decide you need to exchange your mattress then you may be in a somewhat difficult position (depending on the other mattresses they have available) but the information in post #2 here and the posts it links to should help you to make the best of a difficult situation.
Phoenix