You are having disc bulge at low back, Manipulative physiotherapist like me can, pusg the bulged disc, back to it's normal place

Chiropractic Mobilization will help. Do the cat/cow stretch. Get on all fours, with your arms straight and your hands directly under your shoulders; your knees hip-width apart.

I think a proper biomechanical evaluation is a must in your case. Unless the condition is specifically diagnosed, no advices can be given as such. It may be a chance of muscle strain injury due to repeated stess, a ligament injury, joint damage (usually facet joint of vertebra or SI joint) etc. Even if a person is fit and healthy, there will chances of muscle imbalance, due to wrong posture, poor biomechanics in games and activities etc, in your case constant sitting and forward movement may have caused repeated microtears in muscle or ligament in the lowerback. Just core exercises alone won't help you, you may need appropriate rest, electromechanical treatment for accelerating the healing process, Therapeutic taping to isotate the area from repeated stress at work and activities etc. If a proper elevatution is done by a well qualified physiotherapist and differentiate the exact cause, then the recovery will be much faster, as there are tailored treatments regimes for each specific conditions.

Hmm. Posture corrections must. Use soft pillow for back support in your chair. Spine stretching exercises. Physiotherapy treatment keep continue. Avoid  toward bending. Take supine position and Keep towel roll under lumbar spine and move all direction with knee bend.

I think a thorough biomechanical evaluation is very essential in your case. In a otherwise fit person, chances of faulty posture & muscular imbalance in different core muscles & upper back muscles & microtears to intervertebral ligaments, which R a big number in the vertebral column still remains due to sports activities nd faulty sitting posture for 9 hours in the same chair. Its the microtears in ligaments & muscle strain. U need to take complete bedrest for 7 days wd light diet,i.e. more fruits +salads & less cereals wd lumber corset use when walking for at least 1 month.                                         Physiotherapy : S.W. Diathermy+ IFT+Tens + Ultrasonic+ Laser on all pain areas. Dry needling, Cupping therapy will provide high relief. Get MRI done  for lumber region--a must. All this Physiotherapy for 20-25 days. Have 2 sessions Physiotherapy daily on 1st 7 days for faster relief. Can consult me free on Video call through Practo. Only lumber fascia stretching --one month, Myofascial release 10days is to be done. Core exercises to do after a month of Physiotherapy which even may not be needed in your case. Learn proper posture of sitting in chair-must.

Biomechanical assessment of your body will diagnose your problem. Consult a experienced physiotherapist. Looks to me a issue of inappropriate muscle recruitment.