I'm glad you are feeling better now.
Another doctor recently asked whether they had cultured the infected fluid/area to see what the infection was, and when I told him no, he immediately swabbed the area and sent it to the lab. The finding of staff (a very common bacteria on human skin) told them that it had entered the wound during or after the surgery, when the wound was accessible since the incision was not yet healed. That's why they know it was there prior to radiation. And, after surgery the tumor bed naturally fills with fluid (the body's response to the newly created "hole"), and then the radiation "cooks" it and makes it become a problem.
I've learned at this point that doctor's typically react to symptoms rather than considering the possiblity that the stereotypical course of action may not be the correct one at the time.
Best of everything to you.
Liz