Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. Sciatica afflicts millions of people each year—though not as many people as think they have it . A growing catchall term among the undiagnosed for all manner of back problems, sciatica is a specific lower-back nerve condition that requires specific action to address. “Early detection matters,” John Gallucci Jr. MS, ATC, PT, DPT, the CEO of JAG Physical Therapy , tells Popular Science . “If you start feeling sciatica pain, do not wait to get it treated. Prolonging the pain will only make it worse.”  So, anyone seeking sciatica stretches and exercises should be certain they’ve received the right diagnosis for what they’re suffering before embarking on a concerted effort to relieve it. Once they do, however, they’ll find that sciatica can be improved fairly simply. We asked Dr.…