The most important consideration while reading is to avoid reversing the forward curve of the neck for prolonged periods. Do not read in bed, either propped up on your elbow, or with your head up on pillows. Doing so loads stress on to the joints of the lower neck and increases nerve irritation. The results are a worsening of neck pain, headaches, arm and shoulder pain, and numb sensations in the hands. Instead, choose a chair that is supportive to the low back, and allows support to the arms for positioning the book or kindle at a more appropriate eye level.
The same is true for working at the computer. Avoid chairs that don’t support the low back. Position the screen so that you avoid leaning forward to see the text. Bifocals are another common problem in that they require the prolonged extension of the upper neck to see out of the magnified portion of the lens. Use appropriately magnified reading glasses instead, and position the monitor to be at eye level