Tore right thigh start of football last season, and last night got a dead leg in same spot, should I be worried?
Yes, physician eval. You appear to be describing a significant injury to your quadriceps (thigh) muscle. You should be evaluated urgently in case the injury warrants more than the routine management of a major quadriceps strain, such as an actual surgical repair.
Maybe. Muscle injuries like this typically heal with fibrotic tissue ("scar" tissue) and can be susceptible to new injury. I would seek evaluation by an orthopedic specialist to assess the severity of the injury. A hematoma (collection of blood) within the muscle can slow recovery if not treated adequately. Sometimes, an injection in the injured muscle can hasten recovery.