To permanently eliminate the back pain, I would advise the following tips:-
1. Never study with a sleeping or a bent sitting posture. Always sit for study or reading in an erect posture. Best thing to do would be to sit on a straight study table chair.
2. Join yoga classes as soon as possible and you would see the results in 6 months time. It is the best way to eliminate any back pain issues forever and not just cure them temporarily.
3. Do not use any pillows to sleep on your bed. Also, if possible, try to get a new mattress made specifically for people with back pain.
4. Get a proper check-up done with a doctor to ensure it is not a serious issue, but do not resort to any pain killers.
5. Do not sit continuously while studying. Try to walk around with the book in your hand every 30 minutes to get your back some exercise. Also, try some stretching once in a while.
Thanks & Best Regards,