Well, it just may be the other way around.
If you have pain or other uncomfortable sensations in your wrist and hand, those are called symptoms. Symptoms have a cause. It’s like when you fall and scrape your knee. The broken skin on your knee is a symptom of the fall.
The symptoms in your hand are caused by something, too. They can be caused by the muscles under your arm. Under your armpit you have muscles that attach from ribs to arm and shoulder. You have muscles in your chest that also attach to your arm.
When these muscles get tight, they can put pressure on the nerves that pass through your arm to your hand. The nerves hate being pressed on and so they cause discomfort in your hand.
Although short muscles that cause the symptoms don’t usually complain, the ones in your armpit can be uncomfortable if they are in a “knot” or muscle spasm.
The muscles on the side of your back, just behind your armpit, can also be involved (those are the “lat” or latissimus muscles). Those muscles can also have pain when they are in spasm or contraction.
So, you see, this is NOT a case of which comes first–the chicken or the egg.
Even if you were not aware of the armpit pain before your hand pain started, the spasm was most likely already there. It is just becoming tighter and more noticeable with time.
It is very possible that your carpal tunnel pain is a result of that tightness in the muscles under your armpit.
Those tight muscles can be the cause of the CTS symptoms in your hand!
The good news is that you can press into those armpit muscles by yourself. It will be uncomfortable because they are tight. Just keep pressing and feeling and assessing the tightness in those muscles. By pressing into those muscles with your fingers, it mechanically relaxes them.
You can also massage, stretch or press into your chest muscles to help them relax. You may be able to grab and squeeze your own latissimus muscle.
If necessary, go to a massage therapist who knows how to do this work and they can help you get rid of the pain in your armpit as well as your carpal tunnel pain.