I'm a rookie. Been playing about six months.
Last week, I had the house all to myself for a few hours, so I jammed away. (I rarely get more than 45 minutes, if that.) The next day, my right thumb (and that fat, fleshy part of your hand right below the thumb) hurt like hell. It even hurt to raise my right arm over my head. Couldn't bend my wrist backwards or hardly move my thumb.
Then it went away almost as fast as it came.
Is this somehow related to the bass? Has anybody had this experience before?
You may want to revisit your technique.
Seriously, I’m about to turn 71, and have been a working bassist since the mid 1960s. My basal thumb joint on my right hand is bone on bone due to the lack of strength of a tendon. It’s is common in older (ok call me elderly LOL!!). I’ve been getting by with cortisone shots, but usually most people opt for a surgical solution, and I may have to suck it up and have done eventually.
I’m not sure how old you are or what shape you are in. I’m also not qualified to offer medical advice. For all I know this episode you went through was just a one off. I will suggest that when you experience pain something is not right. Either something broke or some part of your anatomy was overly abused.
My long term experience playing bass largely has been free of discomfort other than blisters. Even after playing hours playing for hours on end. Even at my age with a looming 3 hour gig this NYE.
My thought is take it easy when you are playing but stop at the first bit of discomfort. Don’t try to play through it, take a break. But if you experience anything like what you just did, a consult with a medical professional maybe in order.
Best wishes.