Not sure if these conditions can be cured, but if you start a daily kundalini yoga practice now, it may help. I have a 70 minute video from the 90's on VHS called Yoga For Life. I used to do it everyday, but now just do Raja yoga and sun salutation and lift weights.
The bass is a big, heavy beast of an instrument. I don't really understand how some guys can play, without lifting weights(unless they are 200+ lbs of muscle). I am not one to sit and play bass either. I play hard with my whole body. Lifting, I do reverse situps, bench press, shoulder presses, bench fly press and more. I practice preventive maintenance on myself and eat healthy and a daily power walk(30+min) No drugs, big pharma except the occasional cigar, beer or Scotch or gin.
Look at bigger straps too. I have a bunch of 4"
Italia leather, that are comfortable enough for me.