Timmy,
There are many,many factors…many,many,many,many factors which can cause numbness. Carpal Tunnel is only one of them and more often than not, what people think is Carpla Tunnel in fact isn’t. This is testified to by the fact that surgery for CTS (carpal trunnwel syndrom) rarely has any long term effect. Short-term, yes, but most time it comes back again.
Unless you are waking up at night with your thumb, index and middle finger only numb or tingling, then you probably do not have CTS.
Constriction in the shoulders caused by squeezing the bag can cause numbness.
I have tinggling and numbeness every now and then after playing the pipes, funny thing is, I can play the whislte or GHB practice chanter for hours on end and not get numbess or tingling, suggesting a constriction problem due to pressing on a bag.
So your problem could very well be simply a muscular problem higher up in your shoulders. Often enough, constriction in the muscles in the shoulders which run down the arm into the hand cause exactly the same symptoms as CTS, which is why surgery for CTS can eliminate the symptoms initially, but a build up of fluids in the arm because of the should constriction only serves to make the symptoms return again.
DOn’t go to a GP - useless - they’ll only suggest CTS and make you wear a splint or have surgery.
Go to an osteopath or Remedial massage therapist. But there are RMTs and there are RMTs. I recommend going to an RMT who also specialises in things like Trigger Point Therapy etc.
In the meantime, just take it easy. It may just be a temporary thing. If it gets worse such that you have symptoms at times that you are not playing, then go to a therapist. People will cite cases such as Hamish Moore, the Scottish piper who lost the use of his middle finger (and has since learned to use his little finger instead) - but remember, he had a very tight and regular performance schedule, performing nearly every day of the week and over a number of years lost the use of his digit.
Cheers,
DavidG