An easy way to see if it's CTS (carpal Tunnel Syndrome) is to slap medium hard on the veins where the hand bends.
If it tingles in your fingertips, chances are great that it's CTS.
Many also experience a tingling sensation in the pinkie finger, before or after sleep and sometimes all the time.
It could also just be the thumb being inflamed, or rather, the muscles in the thumb. Have you tried any painkillers to rule it out?
It could also be tendonitis, which is an inflamed elbow. That usually show symptoms in the hand, pain, et cetera.
(If the elbow is hurting, it's the shoulder, and so on.)
You can check this easily by massaging the muscle on the upper side of the elbow. Put two-three fingers on the lower side of the elbow, towards the hand and press slightly. If it hurts: Muscle inflamed.
(and then, massage it before going to bed, it should relieve the pain)
But yeah, as so many people have said in the thread already, only a doctor or a physio therapist can rule out what's causing the pain!
I'm no physio therapist, but I've experienced all of these and a long time's rest combined with stretching has proven to be the deal in my case.