Dear,
Middle back pain in young adult without any history of trauma and if not associated with fever, weight loss, loss of appetite is usually due to muscle spasms.
Spasm could be due to anything such as lifting heavy weight, sudden jerk etc.
Next Steps
Hot fomentation
Muscle relaxant tablet such as Zerodol-TH4 Twice daily for 3days
SWD/ Ultrasonic therapy application
Avoid cross leg sitting, squatting, heavy weight lifting
Health Tips
If still persists, kindly get the Video Consultation for appropriate treatment.