Sweet spot

Over the past few months I have noticed something becoming more and more prominent.  On elbow in, I hit this “sweet spot” where it feels like everything is locked up to it’s maximum – very stiff almost bone on bone feeling in between the joints, yet muscles are softish.  So much so that the tip of my fingers vibrate as if from reverberation.  I don’t get this feeling from any other movement, so I’m not sure if this normal?