If meditation requires a straight back (ex: chakra opening meditation) and my back hurts and I need focus on my breath and I can’t because my back hurts…. what can I do?

May down. It Will relax your Back and allow breathing as well. You can also lay yourself no a massagem ball or roll to relax more intensely

sometimes it's better to lay down, that way you can stop thinking about keeping your spine straight and simply relax to be able to enjoy the meditation

After meditating, try taking a rest. Lay on your side and take a nice short sleep. Other than that, try to pay attention to how your posture is fixed. Always sit tall to avoid it from aching even more. If those don't help, you might need to see a doctor if the aching worsens.

Try doing it up against a wall, or with a few soft pillows behind you. This will allow you to rest into proper posture, and hopefully reduces some of the pain.