General :: Correcting Words After Typing Them?

where my phone wont scroll accuratly. Ill go back to try to fix an issue say 3 lines up from where I am and it wont scroll to the correct place I tried to place it. also if you get the cursor where you want it to fix a mistake getting it to go back where you were typing before trying to fix the mistake is a headache. Itll recenter the screen once yoy try to click back to where you were typing so you cannot see where or what your typing. I currently havr the nexus s but my evo4g did it to. The nexus is worse though. Sometimes its fine but uaually it isnt.