A grieving mom sobbed in Manhattan Supreme Court yesterday after the murder arraignment of a man accused of randomly shooting her son on an East Harlem street this summer, just two months before he was to go off to graduate school.

“I just miss my son so, so, much,” Paula Shaw-Leary said of Matt Shaw, 21, the youngest of seven siblings.

“He went to the store for a snack, and he didn’t come back,” she said. “I wanted him to be out of New York. Everybody has guns.”

He’d been scheduled to start classes this week at SUNY Albany for a Master’s Degree in economics.

Shaw died after he was shot in the predawn hours of July 5. Khalid Rahman, 20, pleaded not guilty and told cops that all he did was break into a run at the scene because “these guys” had been chasing him and firing shots in his direction.

“This young man had a bright future ahead of him — instead he will be remembered as a tragic victim,” DA Cyrus Vance, Jr. said of the victim in a statement issued after the arraignment.

Shaw was one of nearly a dozen victims of deadly shootings citywide over the Fourth of July weekend, Vance said.