So I just got my new frame and I love it,

However, I feel like I am locking my elbow's out and finding my neck start to hurt around 30k's into a ride.

I currently run a 120mm stem with a 6 rise. I was thinking about getting a 100mm with a 7 rise.

My question is, is this to small, a decent, or to drastic change? I know how much 20mm can make, but I have never messed with the rise of a stem before.

Thanks for the assistance.