All of the above is valid advice. If you only have the one light off to the right, then a well placed reflector of white cardboard just out of frame to the left will help drive the shadow away.
Bringing light through the background will effect the color of the light falling on the subject. Not a bad thing, just keep it in mind.
If you have two or even better three lights, then bring one in from the right front as your main, a second, the fill light, in from left front but slightly further away to help show the shape of the subject and the third just from the top. Make sure the top highlight does not over power the lighting from the main and fill. The highlight may also be from slightly behind the subject and somewhat on the background. If using a white background, jells can be placed on the highlight to change the background color or add a special touch of a color you wish.
Charles