Constipation

I don’t understand how constipation works. I’m literally ALWAYS constipated, it is literally the worst feeling ever. That’s besides the point. I know it means hardened stool (I eat a lot of protein and the average amount of fiber). To me, it feels like my butthole won’t open, like I can feel it right there but it won’t open. But what actually is happening when you’re constipated? Is it your butthole not opening?