Vibrating Pipe

The fill valve in my toilet went bad so I turned off the water to the toilet and replaced it, but when I went to turn the water back on, the pipe in the wall started vibrating/hammering real bad. I can't figure out what the problem is. Any help would be much appreciated.

If the shutoff valve is a multi-turn job, try replacing it with a quarter-turn ball valve shutoff. My guess is that the washer is old, maybe a little loose, and is the source of the vibration.