When uncrewing the pipe (the piece that the shower head is attached too) from the copper elbow, a small piece broke of inside the elbow.
Most shower head pipes are half inch thin wall. You need to go to the hardware store and buy or find a friend who has a tool called an easy out for that size pipe. That is the easiest way you to get the broken part out and save the internal threads of the mating piece. In a worst case situation an experienced person can cut the broken part out with a diamond point chisel and then clean the threads up with a half inch pipe tap.
There is a tool that is sold in the irrigation pipe department that is used to remove plastic sprinkler pipes that break off. You stick it in the pipe and it digs into the inside and you unscrew it. It is worth a try.
Go to a Home Center or gardware and buy an EZ-out for 1/2 pipe. Tape it into a socket (so it doesn't fall out in the wall) and use an extention to reach the elbow. This will lock into the piece that broke off and remove it.
