Although it might be legal to fish under a commercial fishing pier (Va Beach may have a regulation regarding it but there is nothing in state code or regulation about it) . . . if there are people fishing on the pier you risk damage to yourself and boat inflicted by grumpy pier fishermen.
Not always a good idea.
Others may come in and say that it is a common practice, and maybe it is OK to do it under certain sections of the pier, but this is my opinion.