What does 会 mean in 为什么我会觉得历史课很无聊？
会 has many meanings
in this context, &quot;会&quot; functions as  &quot;would&quot;

Would: modal verb (INTENTION/ POSSIBILITY)
&quot;为什么我(会)觉得历史课很无聊?&quot; = &quot;why (would) I think history class is boring?&quot;
If there's no explanation following the question,  it is a rhetorical question

Example of 'would' as a modal verb :
&quot;If it doesn't rain, I would go&quot;  (INTENTION)
&quot;One of them would die if they fight each other&quot; (POSSIBILITY)