7 herniated discs (lumbar/cervical), no injuries. Diangosis of ddd. What else can cause this so young? (27yrs old) never had a t spine MRI only lumbar/cervical

DDD. This could simply be related to occupation or other ergonomics. Potentially related to ergonomics from childhood sports or posture.
Symptoms? Asymptomatic disc herniations/bulges occur in nearly 80% of the population. Only if there is pain or weakness/numbness should you seek further evaluation. Alternatively, you might consider evaluation with a specialist to determine the need for thoracic mri.