More and more people are seeking injections of anti-inflammatory steroid medications for back and neck pain. In 2011, the last year for which complete information is available, doctors pushed the plunger on 2.3 million steroid injections into the spine — and that’s just among people covered by Medicare. These injections deliver drugs that mimic the effects of two hormones, cortisone and hydrocortisone, to reduce inflammation and help relieve pain. When they work — they don’t always — such injections can bring profound relief. “If you are in severe pain with a ruptured spinal disc and you get a steroid injection, you are going to feel better sooner,” says Dr. James P. Rathmell, professor of anesthesia at Harvard Medical School. “That’s the good