Left thumb problem

[Bassman8416]

hey folks,
I have the dreaded hitch hikers thumb, which in all my years(I'm 49) of playing, has never been a problem until now. The last year, I have been studying jazz and gigging and practicing the most of my lifetime. Once in a while I have pain in the lower part of my thumb. This old jazz guy, who is primarily an upright player says I shouldn't let the thumb bend back the way i have allowed it. That it should be straighter or slightly bent at the knuckle, the way an upright player shapes it. Feels weird, any suggestions? I do line up thumb and middle finger and try to keep the thumb on the middle line on the back of the neck. Pain usually occurs when I am in "first position"..the lower range.
Thanks, any help would be appreciated.

[Infidelity]

I have hitchikers thumb too and I was actually asking the same question.. I have to say that bending the thumb backwards forces you to play in un-relaxed way that's why I changed it and played with my left hand in normal position(thumb not bending backwards).. My hands feel much better now and I can play a lot longer this way.. You might give it a shot.!

Here's my thumb..



on a side note don't call it dreaded hitchhikers thumb.. Here's a thread that would boggle your mind..

How come all these "greats" have very bendy thumbs!?