"it just feels like a chore to read these sections"
For me, I typically find it a chore to read long stretches of lengthy description. The key for writing a chapter like you mentioned is dialogue. Chapters without much dialogue tend to be boring. Obviously this is not always the case, but dialogue definitely speeds things up and engages the reader. I once read that dialogue is the sugar of writing. To keep your reader interested, you have to give them a little sugar every once in a while.
The problem with chapters where your MC is alone is that he doesn't have anyone to converse with (besides himself, but that's not a proper conversation). I find that when I write chapters with little to no dialogue I worry about readers finding it engaging.
A few things you could do to make up for the lack of dialogue:
- Include lots of action. Make things happen to keep the reader interested. A brawl outside his prison cell. A fistfight. Someone trying to escape, maybe attacking a guard. These bits of action will hook your reader into a chapter that might otherwise be dull.
- Interesting internal monologue. Try to make his thoughts thought-provoking and interesting to the reader. Avoid repetitive thoughts and try not to make his thought process unrealistic or too dismal. If he's sitting in a prison cell all depressed with thoughts like "I'm never getting out of here" or "I hate it here, I hate myself, etc." then you will quickly lose the reader.
- Don't clutter. What I mean by this is don't include unnecessary description or words just to fill up a page, especially in a chapter that you are already concerned about being boring. Make it sharp and concise and not too wordy.
- Add dialogue. Even if the guy is in a prison cell alone, you can try to include dialogue to sweeten it up and keep the reader going. Can he hear other inmates talking? Are they planning an escape? Does a guard say anything when he walks by his cell? What about when the MC eats lunch? You could have him talk to the other prisoners in the lunchroom. Or he can even talk to himself, just make sure to keep it realistic.
If the chapter is later in the book where your reader is already attached to the characters and immersed in the story, I wouldn't worry too much about it. Especially if you know it moves the story forward and develops the character. As long as it's not boring the reader will stick through a couple chapters even if there is minimal dialogue.
As for your subquestion, I read Cinder and the rest of The Lunar Chronicles a few weeks ago and she has a few prison scenes which are all very interesting. I haven't read a single chapter by that woman that isn't completely captivating. Marissa Meyer does a fabulous job with balance character devlopment and plot. Anyway, I highly recommend checking out her scenes where the MC is stuck in a prison cell.
There were many interesting elements in her writing that kept the prison scene engaging, but here are a few:
- The MC is a cyborg and has an interface inside her mind (so she can look things up on the internet while she's in the cell and see what's going on in the outside world).
- A few different people come to visit her (one of them brings her a gift which she later uses to escape).
- The MC's internal monologue is not overdone and I think that's one of the things I really like about it. It isn't thought-based, but rather the chapters are pushed forward by actions and events.
- The prison scene doesn't last too long (not more than a chapter or two) and she ends up escaping. The escape was a whole chapter by itself and while I could see how it could have been boring, Marissa Meyer made sure to steer clear of any boringness!
A good author knows how to couple up character development with plot to make scenes that engage the reader in both ways at once. This makes for a really powerful scene. If say, for instance, a main character betrays everyone else in a scene that is followed by a toe-curling fight (or some other action scene; maybe someone dying). It makes the scene very intense in a lot of ways and gives it a lot of depth.
EDIT: I see your note about not having any other prisoners. I think you could still make do with the scene. If you have a lot of interesting elements, I wouldn't fret. As long as it's interesting you won't have a problem. The MC can still converse with the guards perhaps. My advice is to try to keep the chapters of the MC by himself as short as possible. Include all the interesting elements and essential things you need for character development, but scrap the unnecessary description or boring monologue. Good luck.
One element you could try is having one of the guards slip him a note. Maybe the guard is somehow related to one of the MC's friends. The note could say anything. Are they trying as hard as they can to get him out? Are they informing him of what's happening in the outside world? You could do a few cool things with this concept.
One more note: You can add flashbacks while he's in the prison cell. That way, the reader gets some dialogue and a bit of the character's past. A nice tactic. With all that free time in the cell, he is bound to reminisce on his past at some point. Why not give the reader some of that to keep the prison chapters from being too dull?