If its really your back and neck, I would stay away from Blue Streak. It has the absolute HARDEST seatbacks in existance. Also, John Allen seemed to have this thing of making his coaster bottom out at the bottom of the hills real, real hard to that the riders will bounce at the bottoms (see Screamin Eagle @ SFStL). That coaster made my bad a little tender after only a couple of rides.
However, IMO, despite all the warnings, I think you would be fine on Mean Streak, provided you sit in the front of the train. The ride there will be incredibly BORING, but not painful in the least.
lata,
jeremy
--Forget coasters, I'd rather ride Janet Jackson...