What causes tingling and numbness on right arm?

Depends ..: It could be from multiple sources. It could be related to compression of nerves stemming from the neck, armpit(axilla), elbow or (less likely) the wrist area. It could be a toxic/nutritional deficit effect on the sensory nerves, though this tends to affect both sides. It could be from a particular issue within a sensory area of the brain(exceptionally unlikely).