Hi Radhika
1) chair would be decent I suppose..if it was anything it would be my own bad posture that would be causing problems... (not sitting corrctly)
2) I would take breaks every hour at least... bathroom breaks etc
3) pain mainly only bothers me when i'm arching backward but recently has started when i bend forward. doesnt bother me when I'm deadlifiting or bent over rows
4) weather doesnt affect it

Thanks for your reply
Steve