Oh no that's terrible, I'm really sorry to hear about your back pain!! I work a corporate job and have been sitting down for 10+ hours, 5 days a week for the best part of 9 years now so I can completely relate.

I know others have suggested great ideas but have you visited a doctor yet or asked for a referral to a spine specialist? You don't want to have permanent damage and potentially they could suggest something to fix it. In the mean time, I definitely try to do the following

• at least once an hour do a quick stretch or just go for a walk
• Use the standing desk! I know you've got one now so that's great, I recently got one at work a month ago as well and I make sure I stand at least 2-3 hrs in the morning and 2-3 hrs in the afternoon
• When using the standing desk, try to stand with your weight evenly on both feet (you'd be surprised how many people favour one leg when they stand)

All the best, hope you find something to ease the pain :(