I too was experiencing the pains in the chest area (mid breast area spreading up and out). In fact it was so bad I went to the ER. After spending the night for observation and many tests, it was determined to be Acid Reflux with spasms in my esophagus. I was given some medication for the acid reflux and everything cleared up. (I am 14 days post op).
For the itching .... When I get mesquito bites that itch, I used stick deodorant (any brand) on the bite and the itching disappears. Might work for the incision if it doesn't cause any infection.