Why Have I Had Bad Left Sided Tingling Numbness And Pain Under My Rib Cage A Month After A ULL Lobectomy To Remove A Lymphoid?

Hello, I had a ULL Lobectomy with removal of Lymphoid back in April. I believe I have healed nicely. My question is, since about a month after surgery I have had a bad tingling numbness pain on my left side right under my rib cage. I have had a CT w/contrast and recently the endoscope. Every test I have had says everything looks normal. what could this pain be caused by. I am starting to think I am crazy.