Answer:
The simple answer to your question is 'yes', it can be painful. However the idea is to give stimulation for pleasure whilst increasing your exposure and threshold to the stimulation provided by your control box. As with most things connected with BDSM your pain threshold will be increased and more pleasurable over a period of time. It is worth remembering that the control box itself cannot be painful - it is the person controlling and using the box that will detirmine how pleasureable or painful it will be. This is not an electric shocking experience and should not be confused with electric shock treatments.