I’d look to your neck. Often, pain in the extremities is indicative of a pinched nerve situation higher up towards the root of the body’s nerve network (i.e., the brain).
The finger bone is connected to the hand bone, the hand bone is connected to the wrist bone, the wrist bone’s connected to the arm bone, the arm bone’s connected to the shoulder bone, the shoulder bone’s connected to the neck bone and… uh oh. All the body’s wiring (aside from that associated with the head itself) runs through the neck.
If you’re often playing with your head turned so that you can see your left hand, you could be pinching a nerve in your neck, manifesting downstream as tingling pain in the finger. If this is the situation, you’ll need to learn to play with your head facing forward (not looking at your fretting hand). If you have a headstock tuner, stop using that.
Of course the cause of your pain may be something different. If at all possible, see an orthopedic doctor. Take your bass along and explain the situation (don’t be nervous about your playing; he doesn’t care one bit about that — he just needs to see that big weight hanging asymmetrically off your body and how your arms and head are positioned as you play, your hand movements, etc.). If seeing a doctor isn’t possible, a highly experienced bass teacher might be able to assess the situation and give good advice. Regardless, as others have said,
rest (take a bit of a break from playing, even though you don’t want to), take some mild anti-inflammatories and then when the tingling situation stops, gradually ramp back up while paying particular attention to good technique. Again, a few sessions with an experienced teacher could help.
Don’t try to push through tingling pain — you could do permanent damage.
Diet could be an issue — I was getting tingling in my hands from drumming once after going vegetarian, but taking a break and starting on a B12 supplement (a common vitamin) fixed the situation. Regularly taking a multivitamin is a reasonable precaution without much downside that, although it might not solve your issue, it possibly might and could have other benefits. Similarly, get sufficient rest (sleep), eat a balanced diet, warm up [do some warm up excercises] before vigorous playing (this is a biggie for me), don’t overplay, get a comfortable setup with easy-to-play strings, play looking ahead (not at your hand), keep your body relaxed (not holding unnecessary muscular tension, perhaps especially in the neck area) while playing, using good technique, etc. All are reasonable steps that don’t have much downside and could possibly have great benefit.
Looking forward to reading about your eventual success, mmmelatonin!
