Phatz, SORRY to hear you have back problems too! They just plain SUCK!!! Best of luck with any relief you can get!!!

CrazyRonny, Sounds almost like you are having Steering Pot problems with it just turning like that with no input from you. My Box Stock chassis has a twitchy pot, and sometimes when turning slowly it jitters about a mm in both directions very fast. I took it apart and sprayed the pot with electronic cleaning spray, and it helped, but it still gets wonky from time to time. With this chassis I have the Sub Trim 75% to the left to get it to try to tack straight!!! Hopefully one of the other guys can give you some more help. The slight wondering is just something I have learned to live with I guess.
another thing I just thought about is tweak in the chassis can make them act off too. I use the "penny trick" to adjust the t plate for tweak. Youtube has tons of videos that can explain it better than I can try to type it out! LOL
Good Luck getting it worked out! Drew