Hello... Proper ergonomics is the key to avoid long sitting working hours... Instead of sitting on bed try to sit on a proper chair with back support... Practice stretching exercises in between ur work.. keep changing position to avoid stress on particular set of muscles..

Correct posture is nothing but to maintain upper body head shoulder and spine untill lower back  straight in alignment without bending forward/back. As you sit in for long time, you need to maintain it properly to avoid neck back and shoulder pains. Sit on chair instead of bed as chair will be comfortable than bed and is easy to maintain posture on bed.

U must maintain erect posture .use proper back support chair during sittting.

Hii Firstly, You need to follow proper ergonomics i.e proper posture to avoid neck pain. Muscles tend to tighten and weaken if they are in 1 position for prolonged time. Avoid sitting continuously for prolonged time.

Sitting on the bed is a well known initiator or low back pain and postural dysfunction. Take breaks every 40 minutes and use ice for 15 mins with a cloth packing 3 times a day for a week. Start some basic flexibility exercises and invest in a work desk.

Hello! Based on your complaints, it is clear that you are aware of ergonomics and bad posture.