I ve recently started working out and have lost some weight about 20 lbs. I m a 44 y/o male. I m 5-10 170lbs I ve noticed that the lower portion of my left rib cage seems to stick out further and feels bonier making it uncomfortable to lie down on my left side. There is no pain it s just pressure. This was never a problem before. When younger I was thin and my rib cage was slightly visible. It would have been obvious if it was not symmetrical then. I do not drink a lot of milk and haven t for many years. Is this just a calcification and a normal part of ageing?