I started here with Josh and when he suggested to anchor your thumb, I chose the pickup as I didn’t like using the E-String. I have a PJ pickup and the P seemed like the logical choice. As I’ve been playing more and faster, that screw at the top of the pickup is screwing me 
. I start digging in which starts digging a whole in my thumb, then I start to move my thumb. What good is an anchor if it moves? So I tried the J pickup. Great for my thumb, but too far back and too close to the bridge. So multiple issues, not fond of playing that far back (got over it), if I wander too close to the bridge the sound suffers, and the strings seems to be affecting my fingers more (the strings don’t have a lot of give back there which actually cleaned up a lot of my string vibration but was hell on my fingers). Friday night I overdid it, played for hours back there and Saturday woke up with a painful callus on my right middle finger. Tried to play a little yesterday but it was bad. Did a little today, still affecting my plucking but I could get by. Maybe I’ll learn how to rest on the E string. I tried moving forward on the J but didn’t help much and was uncomfortable.
I ran onto the same situation several months ago on my pj yamaha. Installed a thumb rest that so far has helped me quite a bit.
@Lanny, that looks like just what the Dr. ordered, great idea.
is that a standard item in a guitar shop? Now to solve my next problem, the song I’m learning is fast and when I try to play fast, I pluck too hard and lose technique and I’m killing my hands. I learned it at 50%, moved up to 75 which is pretty fast but I could play it calm. Something about 100$ though, I’m too frenetic.
I ordered online. Can’t remember who I ordered from, but if you google up “thumb rest for bass” you’ll come up with numerous options…
I have this same problem a-lot… Not near as fast as I use to be (must be an age thing). When I have to plat a really fast song now (typically rock), I use my BEAD bass since I can move much faster between frets and strings when I play it in the EADG range of the fretboard.