Hi Down2Earth,
It certainly sounds to me like your mattress isn’t suitable for your body type and sleeping positions. It’s also possible that neck and shoulder issues could be related to your pillow (to the degree that any mattress or pillow may be connected with medical issues).
This would indicate that the design of the hotel mattress would be more suitable for your specific needs and preferences. Hotel mattresses are usually anything but “high end” mattresses although they are usually newer than most mattresses that are in people’s homes (you can read more about hotel mattresses in post #3 here).
There are too many variables and unknowns for anyone to recommend a specific mattresses for someone else out of all the many thousands that are available (see mattress firmness/comfort levels in post #2 here) but there is much more about “how” to find a mattress that is ideal for you in post #1 here which has all the basic information, steps, and guidelines that can help you make the best possible choice.
Some of the better options and possibilities in the Jacksonville area I’m aware of are listed in post #7 here.
Phoenix