The drain on my kitchen sink has come out. I have attached pictures. I am unable to get the drain hose to go back in and I don't see anything broken at all i.e. missing parts or such. Any help would be appreciated.

Sorry I forgot to add the pictures.

If the chrome pipe in 1 goes into the hole in 2, it appears you are indeed missing parts. It looks like threads on the pipe in 2. If that is the case, there should be a washer and nut, looks like
1 1/2", like the way the pipe in 1 is attached to the bottom fitting. Clean off the caulking, put the nut on with the threads up, slide the washer on with the bevel up, push the pipe into the hole and tighten the nut. Picture 2 is blurry so I an possibly guessing about threads.