Considering your Age and Job hours... your problem seem to be entirely postural/muscular in nature.... You have described as Mid back pain... are you sure its not your Lower back... if you say mid back the chair back rest seems to be the major culprit ...Go in for Ergonomically designed chairs... or else your problem will keep recurring .... It will be beneficial for you to do core and static back exercises... which will make your lower back muscles strong.....However you can also do trunk rotation exercises and scapular strengthning ex which will target your mid back... if you are fond of swimming ..its a great way to stretch and destress your body including your spine. Also if you travel long distances on 2 wheeler...do cut back on it. Take care.

Hello, Your muscles are not very strong to take sustain pressure. Frequent break will help you, but for a short period of time. Try to improve in your posture while sitting and undergo supervised exercise training for your core and back muscles. If your muscles are strong, this issue will not reoccur.