As there are many causes for the numbness and aching of the arms, you should first try to find out its origin. But it is always beneficial to massage both arms from tips of the fingers to shoulders as often as possible. You can also treat your numb arms with your own fingertips.
It is also beneficial to press the acupressure points indicated for neck and shoulder tension and pain and wrist pain. If you want to learn more about how to treat aching and numbness of the arms, order my book Treat Yourself with Acupressure at Amazon.com