Swelling on left side (ribs)

There is a lot of post-op swelling, so it is likely just that. If it goes on for days/weeks, could be a seroma--a temporary build up of fluid that usually resolves on its own, but can be drained if your doc thinks it's necessary. Another possibility is lymphedema which is chronic swelling caused by removal of lymph nodes, but you really need more healing time before considering that. Assume you will see your surgeon soon for follow up, yes? Ask about it then, or call tomorrow if you want to be seen asap. But right now, just get some rest and take it easy--you are fresh out of a big surgery. Good luck and happy healing!