[JeanMarcS]

Well I’m a near 50 overweight guy (yeah, I know...) and sleeping on the side (if I sleep on my back I snore like hell).

If I sleep on a too firm mattress, I confirm my shoulder starts to hurt during the night. When I’m sleeping, I can rest for several hours, even the whole night, without moving or changing side.

But on firm mattress I wake up several time during the night to change side.

About the orientation, it’s really strange, and I cannot explain why, but it depends. And I mean the side is VERY important, as I can’t fall asleep if I’m on the « wrong » side.

But it’s not always the same side. And sometimes it lasts for weeks or even month. And one day I switch for no reason I can find, because it’s impossible to fall asleep on the side I’ve spent weeks sleeping on.

Strange.

[BozeWolf]

Side sleeper here, i have very firm mattress. Shoulder pain is probably not because of the mattress, but because of weak muscles. Training your upper back/shoulder muscles just a bit will help a lot. I had a shoulder injury (bar/pub accident, yup.) which caused me to avoid using certain muscles. Got pain in my shoulder as well. Fysiotherapist recommended some excercises and it disappeared.

I have a firm mattress because i had a sore back, which in turn caused me to wake up tired.

A sitting non physical profession is the cause of all this. Sometimes i do have a sore back, but going to the (climbing) gym fixes it for weeks.