DX ngu from oral sex from unknown female. All std neg inc MG. Doxycycline taken by me & wife. I still have symptoms but neg swab. Should I be concern?

No worries. There are mysteries about NGU from oral sex. Many (most?) cases probably are not STD in the usual sense, just the urethra's adjustment to new bacteria that don't otherwise cause disease. Symptoms often persist after treatment, but no harm is known to result if no discharge or other evidence of inflammation. No disease has been reported in men's regular partners, but Rx is routine to be certain.