Can you suggest the type of mattress to buy

I am 5ft 7ins tall, I weigh 15.5st and I have 46in chest. At the moment I have a memory foam top section with 2000 mini springs underneath. I am a side sleeper and I having trouble across my shoulders and kneck and sometimes my arms from the elbow to the hands feel cold when I wake up. Sometimes that can be 2 - 3 times per night. Can you give me any advice on the type of mattress to consider buying?
Thank you.