I have a 2008 Ram. I just had the heads replaced and now the oil pressure gauge is dropping at stop lights. Upon acceleration the pressure rises to normal and everything is fine except for this minor issue. Thanks for all suggestions in advance

 

Replace the oil pressure sensor.

 

If you have one of the large auto parts stores nearby, consider getting a mechanical oil pressure gauge as a loaner tool.
Are you hearing any valve clatter?
Oil level is correct viscosity and proper fill level?
I agree that new pressure sensor is good first step.