Hard to say for sure if it is a pinched nerve but as suggested earlier could be misalligned pelvis, or sacroiliatis, piriformis syndrome. All 4 could could bring on buttock and slight referral pain.
Vit D3 and
B12 deficiency(mainly Vit D3) could bring on general aches, pain and stiffness.
We need to do a proper assessment to diagnose the issue
Next Steps
Sitting: please take a break every 40 mins as ur disc loading would reduce
sit properly....a physiotherapist would suggest a few strategies
Health Tips
avoid lifting, pulling, pushing heavy weights for the moment...
make a physiotherapist appointment