why is bob ewell still causing trouble for everybody connected with the case

I assume you are referring to after the case was concluded. Bob Ewell had his "fifteen minutes of notoriety". After the trial, he was back to being Bob Ewell again. He could not hold down a job and wandered the town drunk as he had been before the trial. There is the added humiliation of the town knowing the truth. Atticus may have lost his case but he certainly revealed the truth that Bob Ewell is a vagrant who abuses his daughter Mayella in the worst possible way. Consequently, Bob Ewell continued to harass the people he held responsible for his humiliation.