I am experiencing something similar after my recent surgery. I had a colectomy and a blockage cleared up. My pain sounds just like yours, it feels like pressure in the butthole/tailbone area. I can't say its exactly the tailbone, but more like just pressure and an annoying sensation that is just uncomfortable and yes it makes it hard to sleep at night. I figured maybe its from me sitting so much after surgery and sleeping sitting up, but its just odd. I have not said anything to my doctors about it and will see if it clears up in a couple of weeks, or months, or after I do chemo. I tried tylenol extra strength and it doesn't seem to work for it.
The sensation again is just odd, like pressure on the butt middle area to tailbone. Sorry I don't have more information, but yes its annoying. I don't really want to talk to my docs about it cause I am so sick and tired of doctors at this point
RC T3N1M0 12/16
MSS - NRAS Mutation
Chemo Rad, CCR - W&W 5/2017
CT Scan 11/2017 Liver Met 5.5cm Stable, Stage IV
LAR/Liver Resect 4/2018
CEA highest 500, lowest .8 throughout process, waiting for latest
Recurrence left vesical/pelvic sidewall - 10/7/2019 resect perm bag,
CEA rise Feb/May 3.7, 8.8, 30, Recurrence in Pelvic
CEA 40 right now, but was 57, so folfiri to beat it back down.
Lots of chemo for the past 4 years.