On 5S with 8.1.3 mine sometimes does not always in certain apps scroll smooth either or when I first turn it in in the morning, It then clears but nothing that bothers me as it has done it for awhile. Call Apple support to see if you have an issue or like me I live with it and it does not bother me any longer.
I'm having the same issues it makes it so tedious to use I really hate typing on my iPhone. I'm still on iOS 7 I'm waiting on 9 hopefully would be a lot better.