My question could be a follow-up of this question.
This is what happened:
- I took out the rear wheel to make sure I would be able to do so in case of a puncture with the tools I was going to take for the trip (and unfortunately I did not shift to smallest gear, maybe that was a mistake)
- Apparently I put it back in the wrong way, because something was wrong with the rear gears (skipping, making noise like the chain is trying to jump to another gear, and most importantly: they are off by one, i.e. 7th position of the lever moves to 6th gear, 6th position to 5th gear ... etc.). N.B.: I see no visible problem with the wheel, i.e. the axis seems to be seated all the way back on both sides.
- I used the bike for 50ish km before I had the chance to better inspect it
- I was going to try what the answer to the referenced question suggests, namely take out the wheel and reseat it, and here came the problem.
- The nuts and washers holding the wheel can be removed on both sides.
- The axis on the left side (i.e. the one without the derailleur) seems to move freely
- The axis on the right side, though, doesn't move at all: however, again there is no "visible" problem of what is holding it so tight (nut and washer are removed, and it does not look stuck).
- In case it matters (I don't think it does): the bike was upside-down (i.e. standing on the saddle and handle bar) when trying to remove the wheel. (But the left/right sides from above refer to the bike as if it was with wheels on the ground, and you were standing behind it, or riding it.)
Anyone saw a similar problem previously? What can be the reason that it is stuck, and what can I do to unstuck it?