anal "nodule" just removed- from past surgery?

[zinnia1]

I am brand new here! And just had surgery. Just had a bewildering "knot" removed from near anus yesterday. Not a hemmorhoid. Not a new pus filled abscess.. 26 years ago I had a hard labor and delivery and got a thrombossed external hemmorhoid- which unfortunately doctor lopped off a few day after delivery. Then of course skin shrunk back to normal and new incision retreated into anal canal where it tore. A fistula to outside developed which I dealt with for about 9 mos before I could have surgery and wasn't nursing baby etc. Fistula scar periodically annoying, and three years ago had a nasty external hemm that lasted three mos. But over course of last year I have had a painful lump that comes and goes in same spot- but never "forms" into anything. Surgeon yesterday said it was like an old cyst or scar tissue and he was bewildered. No signs of fistula which I am so concerned about. I don't see him for a month, so I am a bit confused how this happens? Old injuries rising up?