Physical symptoms of improper mattress (too firm or too soft)

Hi, question for any expert. So I’ve been under the impression that you only get back pain if the mattress is too soft. And maybe some pressure soreness and joint soreness if the mattress is too firm. I’ve been trying to logic out whether the issue with my mattress is that it’s too firm or too soft (not enough support). I thought it would be a no brainer before the purchase but it doesn’t seem as easy as I thought.

I have a feeling it MIGHT be a firmness issue (too firm) but i do have back and pelvis soreness, weakness and tightness and everywhere I’ve looked on the internet it tells me that means the mattress is too soft.

It’s weird because I think I’m sure I’m sagging less (when sleeping on my stomach) compared to my old mattress. Why would my back feel MORE sore and stiff? Only thing i can think of is somehow the firmness causes it but how?.. especially if I should be less arched and better aligned on the new mattress.

I think it would be helpful if you’d share your height and weight, and whether you’re exclusively a stomach sleeper of if you switch to other positions. What mattresses have you recently tried and which do you currently have that you suspect may be too firm? Hopefully with that info you’ll be able to get a reasonable answer to your issue.

Hi, I’m 5’9" about 165-170lbs. Athletically built. My go to is stomach sleeping but I have been trying to do some side and back sleeping as well too. I had bought a latex mattress (6" firm core and 2" soft topper—talalay). I swapped the 6" core for 6" pocket coil springs–(~1500 in queen). Berkeley Amsterdam into a Berkeley Malmo essentially.

It definitely feels firmer than any old mattress I still have kicking around but it’s almost like I still sink in just a bit on the heavy parts (stomach area on stomach sleep and butt when back sleep) while feeling it’s firm (too firm?) and holding me up more on the lighter parts (chest etc) thus i think putting my low back/pelvis in that extended arch and causing me low back soreness and tightness. On side sleeping it feels on the firm side and maybe pressure on my knees.

So it’s like it’s too firm but also not supportive enough in the heavy parts? I think. I’m kind of at a loss now. I can definitely feel that extra slight dip and muscle pressure in my back when on the new mattress compared to less of that dip and more relaxed back muscle on one of the older more functional mattresses i have kicking around. Yet, like i said, overall the new mattress definitely feels firmer. I’m out of ideas as to how to rectify this.