I have a newish mattress that I think might be slightly too firm for me, at least for side sleeping. It is a “plush” style innerspring mattress, with some memory foam mixed in with regular foam. I’m normally a side or stomach sleeper, and I weigh around 110-120 lbs. The first week or two after I got the mattress I had a little bit of lower back pain when I woke up, which is not really a problem I’ve ever had before in my life. Sometimes when I’m sleeping on my side, it feels like my hips are hitting against something hard. My previous mattress was a pillowtop, so I guess that’s the level of softness that I need, but I didn’t want to go with that again - I figured I’d get a plush mattress and then put a topper on it if I felt like I needed one. So that’s where I am now.
I’m not really sure what sort of topper to buy - latex or memory foam - or what thickness / softness level, either. It’s already a pretty thick mattress, so I would like to buy the thinnest topper I can get away with, basically (otherwise I’ll need a stepstool to get into bed…). Lots of people seem to love memory foam, and it’s cheaper than latex, but I’ve seen some scattered comments that it doesn’t work well for lighter people, which concerns me. I’ve tried out memory foam mattresses in stores and I felt like I was laying on hard quicksand, but I don’t know if putting a small topper on my current mattress would give that same feel or not. I only ever came across one latex mattress locally, and it was weird to lay on - it felt like the top layer of foam was that eggcrate style foam, and it was somehow simultaneously really bouncy and hard. So I don’t know if that was just a poorly designed mattress (it was by a company that normally makes innerspring mattresses) or I just don’t like the feel of latex.
A pillowtop is a method of construction (not a firmness level) so a pillowtop mattress can be either softer or firmer than a mattress that doesn’t have a pillowtop depending on the design and the relative firmness of the materials and components in each mattress.
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” 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.
There is also more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
These posts are the “tools” that can help with the analysis, detective work, or trial and error that may be necessary to help you learn your body’s language and “translate” what your body is trying to tell you so you can identify the types of changes that have the best chance of reducing or eliminating any “symptoms” you are experiencing … at least to the degree that any symptoms are from your mattress rather than the result of any other circumstances or pre-existing issues you may have that may not be connected to a mattress.
The most common (but not the only) cause for lower back pain is a mattress that is too soft although a mattress that is too firm and has comfort layers that are too thin and/or firm to fill in the gaps in your sleeping profile can also lead to lower back pain as well.
Your situation is also complicated by your two sleeping positions which have opposite requirements. Stomach sleepers generally need thinner comfort layers to prevent their hips and pelvis from sinking down too far and sleeping in a swayback position while side sleepers typically need thicker/softer comfort layers to help their hips and shoulders sink in more to relieve pressure points and to “fill in the gaps” in their sleeping profile in the waist area.
For those who are combination sleepers and aren’t able to avoid stomach sleeping then a mattress that is as firm as possible and “just barely enough” in terms of softness to relieve pressure points when you are sleeping on your side would be less risky in terms of alignment when you are sleeping on your stomach.
I don’t know the specifics of your previous mattress or the specifics of your current mattress and how your experience on it is different from your old mattress but it sounds like you didn’t have lower back pain on your old mattress … is that correct? What was the reason you decided to replace your old mattress?
If your old mattress was softer than your current mattress and you didn’t experience any back pain then it’s more likely that your current mattress may be too firm for you.
Latex and memory foam are very different materials with very different properties but the choice between them is more of a preference and budget choice than a “better/worse” choice. There is more about some of the differences between memory foam and latex in post #2 here but the best way to know which type of materials or mattresses you tend to prefer in general would be based on your own careful testing and/or personal experience with each material in a range of different firmness levels.
If the only issue with a mattress is that it is too firm and there are no soft spots or sagging in the mattress then a good quality topper can certainly be an effective way to add some additional softness, “comfort” and pressure relief to your sleeping system but the only way to know for certain whether a specific mattress/topper combination is a good “match” for both of you in terms of comfort, firmness, and PPP is based on your own careful testing or personal experience on the combination. If you can’t test the combination in person then there will always be always some risk and uncertainty involved in adding a topper because the specifics of the mattress itself along with your own body type, sleeping position, and preferences can affect which specific topper would be a suitable choice on any specific mattress.
There is more information about choosing a topper and a link to the better online sources I’m aware of in post #2 here and the topper guidelines it links to which along with a conversation with a reliable and knowledgeable supplier (that can provide you with good information about how their toppers compare to each other or to other toppers they are familiar with that are available on the market) can help you use your sleeping experience as a reference point and guideline to help you choose the type, thickness, and firmness for a topper that has the least possible risk and the best chance for success.
Because of the uncertainty that can be involved with purchasing a topper where you can’t test the combination in person … a good exchange/return policy can also reduce the risk of an online topper purchase so I would make sure you are comfortable with the options you have available after a purchase and any costs involved just in case the topper you choose doesn’t turn out as well as you hoped for.
If a mattress/topper combination does turn out to be a good “match” for you in terms of “comfort”, firmness, and PPP then having a separate topper also has the advantage of being able to replace just the topper without replacing the entire mattress if it softens or breaks down before the upper layers in the mattress (which is very likely because the upper layers of a sleeping system tend to soften or break down before the deeper layers) or if your needs or preferences change over time.