Thanks, that helps. Firstly, your baby will be very comfy inside you! He might wriggle about if you change position but you certainly won't crush him. He's got loads of fluid to cushion him and protect him. I don't think they feel your pain either, it's more that he'll sense your stress.
My tummy hurts too if I lie down on my side, whether that's on the sofa or in bed but more because the weight of my bump pulls tummy to that side, so your sides will get sore if your bump isn't supported. That's why I suggested supporting your bump with something. Even if you are sitting on the sofa, build a wee nest to one side and try leaning over to that side and see if you can get comfy, but remember you'll need more cushions or pillows round/under your bump to take it's weight.
Every now and then I have to sleep sitting up because of the pain in my hips but it really doesn't do your ribs or back any good. Are you due to see your midwife soon? I was offered a physiotherapy class which I found very useful, and also they can show you some positions with pillows and things that support your body and are good for your circulation.
Hope this helps, I know how frustrating lack of sleep is!! x