Hi ryanfred,
While it’s not possible to “diagnose” mattress comfort issues on a forum with any certainty because they can be very complex and there are too many unique unknowns, variables, and complexities involved that can affect how each person sleeps on a mattress in terms of “comfort”, firmness, and PPP or any “symptoms” they experience … there is more about the most common symptoms that people may experience when they sleep on a mattress and the most likely (although not the only) reasons for them in post #2 here (at least to the degree that any symptoms are the result of a mattress and not the result of any pre existing issues or circumstances).
While I can’t know for certain … it’s possible that your shoulder discomfort could be a pillow issue because one of the most common causes for neck and shoulder issues is the pillow you are using. A suitable pillow is an essential part of good alignment for the head and neck and upper body and can reduce some of the pressure on your shoulders because the gap between the head and the mattress and the curve of the cervical spine needs to be supported just like all other parts of the spine. Like mattresses … there are certain “needs” that depend on body type and sleeping positions but with pillows, personal preferences plays a more important role because the face is much more sensitive to textures, temperature, smells, and other more subjective “feel” based properties of a pillow. There is more about choosing pillows in the main pillow topic here.
Your mattress is one sided so it can’t be flipped but it can certainly be rotated (see post #2 here).
Each person’s experience on a mattress is unique and a mattress that is “perfect” for one person may not be suitable for someone else (even if their body type, sleeping positions, or individual circumstances are similar) so your G’ma’s experience may not be relevant to someone else but I’d certainly be interested in any updates about her experience you may have the chance to share. If you plan to provide regular updates for her rather than just one or two then I would suggest starting a new topic where you can post on a more regular basis about her experience so they are easier to follow and don’t get mixed up in a more general topic that is being used by many people.
Congratulations on your G’ma’s new mattress as well
Phoenix