So I am being charged with theft in the 3rd degree. I was house sitting for a friend. I had another friend over to watch movies. He had apparently stolen a gun and some vicadin. He was arrested and admitted to stealing the items. He has been charged. So why am I still being summoned to court?

You are being summoned as a witness - probably for the prosecution. It should say on your summons who issued the summons - the defendant or the state.

There is a difference between a summons as a witness and being charged as a defendant. So which one is it, if you are a witness you will testify you let him in the house, that they were alone in this room or that room.

If you say or helped him steal it, then you may be charged with the crime also