What could cause right hand numbness?

Carpal tunnel: Statistically the most common cause by far is carpal tunnel syndrome in which the median nerve is compress as it passes with 8 tendons trough a "tunnel" bounded by a thick ligament and multiple wrist bones. Other causes include bone spurs , nerve compression in neck, elbow, root of the neck, metabolic-nutritional imbalances. If your hand is weak or clumsy see an orthopedist or neurologist.

Pinched nerves: Nerves are like garden hoses. If they are piched then there is less function i.e. Feeling. You need to see a specialist to pinpoint where your nerves are pinched. They can be pinched in more than one place.