Depends on the writer and the story, of course, but I think with the last chapter, there's the pressure to "tidy everything up" or bring every single plot line to a resolution.

Interesting question, I find both can be pretty challenging at times. I probably find the ending a little harder usually though, maybe because I just prefer starting off a new story and so naturally I put more heart and sole into the opening chapter.

I hardly ever finish anything I start. So writing endings is hard for me. As mentioned above the pressure to get everything right at the end gets harder. However since I haven't finished many stories, the chapters in the middle, near the end are hardest for me.

first is always easy but last is realy hell!!1-_-

For me. Because the first chapter is what gauges if the reader continues to read or not.

I am currently struggling with this.

This is exactly why I never end any of my stories! Always so depressing.