Hi risacarpen,
These are both issues that are relative for each person and about the “fit” of a mattress which can only be determined by testing them in person for PPP (Pressure relief, Posture and alignment, and Personal preferences). My role is to help you with how to find a mattress rather than which specific mattress to choose which wouldn’t be possible because of the many variables involved. There is no such thing as a specific mattress that can help with low back issues “in general” because it would depend on the specifics of each person’s circumstances and the cause of the low back issues. The one that you are looking for is the mattress that has the best balance between pressure relief and support / alignment for your specific body type, sleeping style, preferences, sensitivities, and physiology. The goal is to make sure that the design of the mattress is the one that works best for you and that the quality of the materials are high enough that the mattress will keep it’s comfort and support for a longer period of time than a mattress which provided the same PPP but used lower quality materials that won’t last as long.
Once you get to step #3 in post #1 here … then it’s time to research some of the manufacturers and retailers in your area that have the best odds of helping you find a mattress that best meets your needs and preferences. The better options and possibilities I’m aware of in the Indianapolis area are listed in post #2 here.
You don’t need to spend weeks or months analyzing components and foam layers (and I would discourage anyone from doing this because it would be overwhelming in most cases) … just deal with better retailers or manufacturers that can provide you with the information you need to know that the mattress you are considering uses materials that are the best possible quality and value in your budget range. This is why the knowledge, experience, and transparency of the retailers or manufacturers you deal with can be one of the most important parts of a successful mattress search. They already know what you would otherwise need to learn.
Phoenix