To respond to your original question, there is no reason for rowing to create an injury. I rowed 3-5 days per week in college without ever feeling pain (apart from the pain that comes from wanting to collapse and throw up). If you look at the Concept II site, you'll got hundreds of older people rowing gazillions of meters.
It's possible that your form needs to be improved. Perhaps you could stop by a local rowing club and ask them to watch you for 5 minutes to see how your form is. I found myself slumping forward when rowing (I haven't rowed much for 25 years) and had to correct myself. A slump can certainly screw with your neck muscles. Also remember that the finish is to contract your shoulder blades and pull the oar nearly into your chest. This will help prevent the shoulders from rounding.