I'm having upper back pain due to poor posture. i've been working on correcting it but it's hard to catch myself all day, is there any good over the counter posture brace until i visit a doctor. had xrays done, nothings wrong just poor posture.

There are apps: One of these apps can help: https://www.refinery29.com/posture-apps I'm not a fan of bracing if there is no scoliosis or other musculoskeletal lesion. You can still have bad posture with a brace and the brace will will transfer abnormal stress to other parts of your spine. Braces also weaken back muscles due to muscular disuse. Standing desks can help if this is computer related.