I've been trying to stretch out my fingers when playing the bass and for some reason i cant switch from my ring finger to my pinky, it feels like my knuckle on my pinky doesnt set right or it just trys to stay close to my ring finger and not stretch out. Anyways I've been messing with this for about 2 weeks now and could use any advice or techniques on how to get over this.

G-------------------------------2-3-4-5--
D---------------------2-3-4-5------------
A-----------2-3-4-5----------------------
E-2-3-4-5--------------------------------

Index : 2nd fret
Middle: 3rd fret
Ring: 4th fret
Pinky: 5th fret

ascend from the E sting to the G and back down again
practice for like 30mins, in a couple weeks you should have the strength in your pinky to hold or even hammer down..
worked for me..

When I play guitar my pinky will do it too, my pinky is stretched out fine but the knuckle joint sticks or something and it might pop as I'm pressing down on the fretboard but sometimes won't and I just have to stop and lift the pinky finger back up. But it doesn't do it much at all anymore so I don't worry about it. It stopped for me mostly after I started using my pinky more, so maybe you just need to build up the strength in your pinky.