If you have lifted something heavy, and you have agonising pain down your leg into your calf or foot, its best to book an appointment asap but equally as important to see somebody even if its weeks or months after the incident and the leg pain persists. The pain is called sciatica and you will in all likelihood require treatment and a plan to manage your sciatica. Severe cases may require surgery.
More info here; Sciatica: What It Is, Causes, Symptoms, Treatment & Pain Relief (clevelandclinic.org)