If you are not feeling any pain and the transplanted flap is not discolored, you are fine. I had the same procedure, not for reconstruction but because my wound from my mastectomy was too large to close without transplanting a flap from my abdomen. The major concern with any type of transplant is establishing an adequate blood supply so the transplanted tissue does not die (necrosis). In the first couple of weeks after surgery, movement or pressure that causes strain on the transplant can effect that blood supply. If you have not had any problems with it since the surgery, that blood supply should be well established by now and raising your arms, lifting weight, or some pressure against your chest within reason should not be a problem.
If it eases your mind, call your doctor's office. I'm sure he has a backup that can discuss this with you while he is out.