Thanks for writing to us.
As per the history there seems to be nothing major /grievious injury
in your case.The pain increases during sitting due to Paraspinal Muscles' Spasm .
However please do ,
X-Ray AP and Lateral of Neck//X-Ray Lumbosacral Spine AP and Lateral//USG abdomen and Pelvis.
These X-Rays will rule out Spondilolisthesis//USG-Abdomen-Soft tissues and core organs - injury in abdomen//.
Only if any positive reports are noted,then go for CT/MRI
There after Lumbosacral Belt Support//Bed Rest//Not bending or lifting weights//Anti inflammatory will help you recover faster.
Wishing you a speedy recovery.
Dr Lt Cdr ASN Bhushan.