@ kwt7667 I had the same issue with shoulder, neck and wrists hurting while sitting. So got a really good strap and that fixed that, but then feet hurt after 30 min.
How I fixed that is I got a stool from a flea market (the kind you use when working at a lab or test bench) that is adjustable. I made it high enough that I can kinda sit/lean on it while playing…now I can practice for an hour and have zero pain anywhere to distract me (except fingers…my calluses are getting callused now…lol)
@faamecanic Thanks for sharing your experience! I often wondered if I was sitting too low, and maybe I should look into a stool. I think also, my farsighted vision is causing me to slump to see the strings ( they blurr together); eventually I can am sure I’ll have them by feel, but just starting out, I need to see them.
I have small hands myself and have to shift my hand a bit to play with all four fingers. Keep with the course and continue to use all four fingers, soon you will be able to shift and play effortlessly
If spreading your fingers to cover the frets is really insurmountable, particularly at the nut end of the neck, there are a couple of options to a conventional bass guitar which might make life easier.
You could get a short scale bass which would shave about 3 -4 inches off the length of the fretboard (and therefore shorter distances between frets) The other alternative is a ukulele bass or Ubass. By using much denser strings, the scale length of these is around around 21 inches, about 2/3 the length of a conventional bass! These come in fully electric or acoustic/electric versions.
Both these shorter instruments are tuned exactly the same as a standard bass guitar so you don’t have to do any transposing to continue with the course and you can rock out without the pain!
Exactly, @Sheldon and @Steinbeck! . . . 
Nothing happens “instantly” . . . took me awhile (and I’m still working at it)
Cheers, Joe
Yep. It’s just like any other muscles in your body really. Like I can’t touch my toes right now, but I know if I worked on it I could. Or say you want to lift 200lbs and can only lift 150lbs right now, you just need to put work into it. I understand some people have physical issues that limit certain things, but for 99.9% of people, it just needs more effort. Even more so for us older folk in the community like me. 
I recently posted a vid in the “Small hands need help” topic of this kid that looks like he’s 10 or so absolutely shredding on a full scale Warwick.
All it takes is practice. I certainly can’t comfortably do a four-fret spread down below the fifth fret or so. You know, where we spend most of our time 
So I don’t, I just shift.
I can’t either, so I don’t “fret it.” 
I’ll just manage, and I’ll bet that eventually I’ll get there one day and I’ll probably hardly notice. I just trust the process.