Pretty much as it says in the title. My only addendum is that I worry about hot mattresses. I live in a cool place but about a month every year gets pretty hot and I don’t have A/C, so heat management is of moderate importance to me.
I like my shoulder to disappear into my mattress, hence going for softer. My typical issues are neck and back pain (I’m sure neck pain also needs a better pillow than I’ve been using so open to pillow reccs too!). I’m not someone who wakes up with a lot of pain, but it happens!
Hi cymbalmonkey.
Welcome to our Mattress Forum. 
As you’re a hot sleeper, I’d recommend a latex hybrid. Latex sleeps cooler than all other foams, but allows for similar sinking and support to memory foam. Coils under the foam (hence the hybrid name) allow for the traditional bounce of an innerspring, but also allow for a bit of air flow to allow for cool sleeping that an all-foam configuration may not offer. There is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range.
I’m not sure what you’ve read since you found the site but just in case you haven’t read it yet … the first place to start your research is the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones.
There is info about the most common “symptoms” that people may experience on a mattress in post #2 here that may help you identify why you may be experiencing pain.
As for your budget, are you looking at a queen? Twin? Something else?
NikkiTMU