For a while now when i sit i feel a pressure under my right rib cage. and when laying down on my right side i have trouble breathing and can't lay on ?

Get checked: This can be a variety of issues from simple gas in the colon flexure to something pressing under your diaphragm. I don't want to alarm you but since you mentio9ned its hard to breathe it makes me wonder if you lung capacity is diminished on that side. See you doctor a chest xray and possible mri or ct would make the diagnosis easier but see someone.