A man in a wheelchair was hit and pinned by a dump truck in SoHo Friday morning, officials and witnesses said. The pedestrian, whose identity was not immediately released, was struck and pinned underneath the truck at 9 a.m. on Spring Street, near West Broadway, an FDNY spokesman said. The victim had been wheeling his way between cars when the truck struck him, said the truck's owner, Sam Battal, who spoke with his driver by phone after the incident.