When I lay on my side or sit hunched (how I normally sit) I feel a pressure under the bottom middle area of my ribs (assumedly cartilage), it is not painful but very uncomfortable. [When I sit straight up with my back against something hard it's difficult for me to breath] It almost feels like one rib is under the other slightly when laying on my side, however I looked that up and it is not similar to what I'm feeling. This has been going on for at least 5 years and causes me to always sleep on my back only. I was thinking maybe it was fat buildup or something but I havent found anything similar (without pain) and I'm only slightly chubby.
My question is what the pressure is caused by, and how to remove it so I may lay on my side when I sleep again.