You should check your derailleur alignment and you can service the jockey wheels by removing them, cleaning them, and giving them a little fresh grease which will make them run smoother.

A misaligned rear d will throw off an indexed system and will also create a lot of noise... with the bike in the high ring and small cog sight along the jockey wheels and cage to see if it is tracing straight through as with a badly aligned hangar or bent cage the chain will rub against the cage.