I've woken up today with the worst middle back pain (I suffer back problems but it's usually my lower back) it absolutely kills, not so much with movement but more when just sitting or standing still. It almost feels like someone has me in a tight embrace around me middle back and upper stomach. I have gallstones diagnosed but I've not had issues for over a year and this isn't the same type of pain. What on earth could it be.. is it possible it is my mattress. I do need a new one and I'm thinking my mattress is so old and rubbish that it's causing me to be in pain. Any advice? Painkillers are not touching it whatsoever.