Hi karl235,
While it’s not possible to “diagnose” mattress comfort issues on a forum with any certainty because there are too many unique unknowns, variables, and complexities involved that can affect how each person sleeps on a mattress in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and your Personal preferences) 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 that may be helpful.
If your mattress is too soft then some of the suggestions in post #4 here may be helpful. While adding a softer topper can be an effective solution for a mattress that is too firm … it’s much more difficult to “firm up” a mattress that is too soft without removing and replacing the foam layers that are too soft or too thick,
See my reply in your other topic in post #3 here.
Phoenix