This sounds like a condition that I used to get when I did a lot of mileage in the car, I found that the inside of my knuckles (on the palm side of my hand) felt sore to the touch as if I was touching the bone. Is this the same?
It sounds like a repetative strain kind of injury, mine tended to clear up, actually I'd forgotten I had it until I saw your post and it seemed to go as I drove less!
I too fly a 150 and would say I don't grip it too much and I think this is a matter of proper trimming and getting used to it.