See an ortho doc and get an xray to see if you are getting a bone buildup (osteoarthritis) between the trapezium bone (one of the small bones in the wrist) and the thumb metacarpal bone. I do have osteoarthritis there, and it causes pain in the area that you have marked out.
David Bjornstad
1923 Conn New Wonder 86I, Bach 6 1/2 AL
2018 Wessex EP100 Dolce, Denis Wick 4ABL
2013 Jinbao JBEP-1111L, Denis Wick 4AM
2015 Jinbao JBBR-1240, Denis Wick clone mouthpiece of unknown designation
Cullman (AL) Community Band (Euph Section Leader)
Brass Band of Huntsville (2nd Bari)