Questions about back pain deserve an individual assessment. A shirt cannot establish the cause of pain, and its fit should not be mistaken for a treatment or a prevention plan.
Apparel and physical support are different
11X compression shirts provide close-fitting coverage for your warm-up and post-play routine. They are not spinal braces and are not presented as a way to prevent lower back pain. If discomfort is affecting your play, speak with a qualified healthcare professional.
Choose your layer for comfort
Look at fit and construction, then decide how the garment works with the rest of your kit. Bring a fresh layer for after the session and follow its care directions. That keeps the role of apparel clear while health questions receive appropriate attention.