I was in a motorcycle accident 3 months ago and had a really big hematoma that was drained, I got a wound vac, and then had an irrigation and debridement because there was tunneling after the wound vac came off. Since the wound vac came off, I could feel what seems to be like air filling up in my back. It is not painful and it does seem to come when I have gas but I had a CT scan with the fluid, an MRI, and the surgery and they did not find a fistula, so now I am just curious as to if they could've missed it all those times or what. I can feel when I lay on my back and then sit up, I can feel it move, or I can put my hand on it and make it move a little.