@Ciaraioch i have a vision brand chair, something like https://spartansofficefurniture.co.uk/vision-mesh-office-chair
If you're having back trouble at a desk there's a heap of non-lumbar things that'll help.
* Chair needs to be high enough that the arm rests are basically level with the desk (desks are normally too high)
* foot rest needed to support having a chair ludicrously up so high
* Top third of monitor(s) at eye level
* Chair needs to be able to lean so you can lean back and rest
* Wheels surprisingly important too