Hi! I've had surgery before behind my right ear, due to a recurring cyst-like growth thing - the doctors didn't even know what it was really, only that it was harmless. It was basically just a big cyst that kept coming back...it would get bigger and bigger until it would pop, and then come back a couple weeks later. I finally had the sack removed from the area and stitched up, hoping to prevent the damaged cells in the area from growing again - they did a couple of times, but haven't for a really long time now. Unfortunately I'd already scarred the area pretty badly from my own picking at it!
Anyway, the surgery was absolutely nothing to worry about, it was extremely quick and painless! The doctor just gave me a quick numbing of the area while I layed there for maybe 15 minutes maximum, a few stitches and that was it, all done. Really fast, and the stitches came out fast too. I still have a little scar behind my ear but it's not bothersome at all.
Mine could have possibly been a lymph node infection, seeing as the area kept feeling with fluid and what not. I am sure you have nothing to worry about, getting your tonsils out sounds much more serious. Hope this comforted you a bit!