Knot Under Ribcage Post-Tummy Tuck and Breast Lift

Hi- there are many possibilities to explain what you feel (listed below by my colleague). It is also possible that you are feeling the sutures he used to tighten your muscles- in patients who have lost a lot of weight, the skin is often thin and it is easier to feel these through it.
In either case, you need peace of mind that you don't have a problem, and that can only be given by your surgeon after an examination of the area- give 'em a call.

This could be a hernia, it could be a pulled stitch, it could be a resolving neuropraxia, it could be a hematoma/seroma, etc.
There are multiple diffferent conditions which could explain the finding you describe but it is difficult to say without an examination.
Your best route, is to seek evaluation by your treating physician/surgeon to perform a focused examination knowing your unique anatomy.

Cpdmom3,
There are many causes to explain the symptoms you are describing, including a seroma (fluid collection), hematoma (blood collection), inadequate fat excision or liposuction (if you had this at the time of our surgery). It would be unusual to have a hernia at the location that you are describing. The best advice is for you to talk with the surgeon who did your surgery, since he or she know what surgery was done.
I hope this is helpful.