"As you have already most likely experienced for yourself, slouching, or sitting with your spine rounded forwards, causes irritation and discomfort. In some cases, prolonged slouching may lead to more serious injury in your neck or low back.

The pain or discomfort arises for two main reasons. Slouched sitting holds your muscles in an abnormally lengthened position. Doing this day by day, for hours on end stretches these structures abnormally and ultimately weakens them.

Over time, prolonged stretching leads to disc degeneration, the discs being the little cushions between your vertebrae (back bones). Slouched sitting pushes the discs outward towards the surface of your back. In due course, the discs bulge, also called herniated or slipped. Holding your neck tilted forward of your shoulders, and/or with the chin jutting forward, also mechanically harms the discs in your neck spine.

How to fix

Using a lumbar roll is an effective way of ensuring you sit correctly in a chair. Using the lumbar roll effectively requires you to sit deeply into the back of the chair thus maintaining your lumbar lordosis as it rests up against the roll.

Lumbar rolls are available in different sizes and firmness. Ensure you have been recommended or tried a lumbar roll that fits you correctly and for the right setting (office or car). A lumbar roll that is too large may feel like it is sticking you in the back, or extending too high or low on your back. If it is not comfortable, it is not right nor helpful, change it!

Driving

•Sit with your hips all the way to the back of the seat.

•Move the seat closer to the steering wheel so that you don't have to reach forward for the wheel, rounding your spine in the process.

•Tilt the upright part of the seat just slightly backward so that you lean your upper back back against the seat instead of pressing the lower back and reaching and rounding.

Sitting at your desk

•Sit with your hips all the way against the back of the chair.

•Move the seat closer to the desk so you can sit up instead of slouching forward.

•Raise the monitor using a phonebook or block of some sort."

Reference and picture: http://cartwrightphysicaltherapy.com.au/blog/bad-sitting-posture-why-you-need-a-lumbar-roll and https://www.google.co.za/search?q=sitting+on+office+chair+with+lumbar+roll&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiF_Zb_oKnVAhXFAsAKHWIXDhMQ_AUICigB&biw=1084&bih=730#imgrc=br4PqTS5eAgspM: