Sharp pain on left thumb & wrist & spread to forearm which makes it feel very heavy and numb occur most night. Is it carpal tunnel or nerve compression?

Could be CTS. It sounds like it could be carpal tunnel syndrome (cts)which is a type of nerve compression, but this will often affect other fingers rather than just the thumb. Is it on the lateral or outside of the thumb? It could be a tenosynovitis as well. If you look up a test called a finklestein test, you can check yourself and see if its that. If you have neck pain, it could also be a radiculitis.