Since he finds reading hard, it doesn't sound like he's bored because he isn't challenged enough. However, if he HAS already mastered the level of schoolwork offered, then you can talk to the teacher about giving him more difficult work (as opposed to more of the same - which really IS boring). If he's ready for chapter books, there's no reason he shouldn't read them just because the rest of the class is still working on basic letter recognition. That doesn't sound like your son's situation from what you've written, but perhaps that's the case??
Rather, when he says that school work is boring, it sounds like he is expressing a preference for the play activities rather than the academic work. How are academics done with the students? Is he expected to sit still and listen to a lesson and then do a lot of worksheets? That does sound pretty boring, especially if he's allowed a lot of freedom and self-direction with the play activities.
I would explore his dissatisfaction a little more and get a good idea of what he dislikes about the academic side of school. Then I'd talk to his teacher about possible solutions.
For example, can he choose which books to read or are they assigned? If he has a choice, has he tried all the books in the classroom that interest him? Does he prefer to read about certain topics? Some kids aren't interested in fiction and prefer books about favourite non-fiction topics, eg. dinosaurs or the solar system or airplanes. Perhaps you can send some new books from home.
If there is a current read-aloud that you are reading together at home that he loves, perhaps you can read a chapter together at night and then send it to school for him to continue on his own. He may be really motivated to read, just so he can find out what happens next.
Do they practice letters and writing only with pencil or crayon and paper? Are there different methods offered to work on writing skills? How about finger painting or drawing letters and words in cornmeal or sand on rimmed baking tray?
Is this a fairly recent complaint? If so, have things changed in the classroom? It's possible that during the first term, the teacher took a more play-based approach to the class, particularly if there were a lot of children who never attended pre-school. As they enter the final half of the school year, perhaps they are becoming a little more structured and spending more time on academics, to prepare for 1st grade. I'd talk to the teacher about how he is coping with such a change and whether there's anything that might help him to adjust.