Continuously reading books or working at the screens for hours in a single stretch puts a lot of stress on the upper and middle back as the spine is kept misaligned for long.
Therefore, ensure that you are sitting in proper format which should cause least pressure on the back. Place your bottom to the back of the chair so that your back is supported properly. Your shoulder blades should touch the backrest, foot should be flat on the floor and your knees lower than your hips.
For every 45 minutes on the desk, take one minute break and do rotational stretch or twist your back on the chair itself to touch the back of your chair and then repeat on the opposite side (do this 5 times) and drink a glass of water or fruit juice. This will keep your spine healthy and hydrate your vertebrae (long hour sitting and gravity squeeze water out of the disc) help you alleviate your pain.
As far as asana is concerned, you should follow your study by bhujangasana, tiryak bhujangasana (rotating your neck towards left to see your back and hold and then move your neck to right and hold). You can practice 3 rounds of bhujangasana, for 15 seconds each. Thereafter, you should relax in makrasana with mentally reverse counting from 20-0.
In the morning, you should practice suksham vyayama for neck, arms and shoulders.
