When I exercise fast chord changes on my acoustic guitar( just open chords, no barre), after about 10 minutes, I feel contraction on my palm near the thumb( on thenar eminence). When I touch there, I feel a slight numbness. It is not my first month on the guitar, I did not feel that pain even I am practicing barre chords, but I have never exercised that much chord changes before. My palm is not touching to neck, my thumb is on the back of the neck nearly all the time and I'm trying to press close to frets. I practice around 20-30 minutes, 3-4 times a day( total 1-2 hours).
Edit: I have found something interesting, when I make a fist and bend my wrist inwards, I feel the muscle/nerve(on thenar eminence) which I'm talking about is like popping, something like a string is conracting.
Should I practice less or let my muscles workout?