I taught myself how to play with a pick a few months ago just to have the ability if I ever needed it. Because of this, I only played with a pick during my practice sessions. After becoming used to it, I tried to go back to playing with my fingers and things went well at first, but once I attempted songs that required speed, my fingers would sometimes lock up; unable to play.

When I first learned bass, I would do simple scales with my fingers to build dexterity in my right hand, but even those I'm now having issues with. Can anyone recommend me some decent ways to build my right hand ability back up? (I'm aware of the possible innunendo in that sentence)

Any help is appreciated.