I had a repair of an graft replacement of the decending portion of my aorta,jusrt below the arch.the inscion was from my back under my left arm.i have a small collapse in my left lung and after eating i get a bubbly sensation in lft throat and back?

There are no details regarding the time since surgery and whether the surgeon has seen you since the surgery. You had major surgery involving the largest artery in your body and the symptoms although NOT suggestive of a serious complication, require evaluation and a detailed explanation to you. Please contact your medical doctor and the surgeon.

Without the time frame (when was the surgery, when did these complications develop), how you know you have a collapsed lung, and the specifics of your procedure, no one can answer this question which is nevertheless beyond the scope of an on-line forum. There are several potentially life-threatening explanations for what symptoms you do describe. Talk to your surgeon or go to the ER NOW!