Please give some suggestions to ease back pain.

Depends. If you are getting recurrent common back pain and discomfort then it could be a sign of weak core muscles in back and abdomen. Also it could be due to poor lifting mechanics etc as well. If it persists see you doctor, otherwise recommend yoga or pilates as exercise regimens to help with your back. Also wear good shoes and sleep on a supportive mattress and use tylenol (acetaminophen) +/- Ibuprofen for otc relief.
Hate to be judged. Any physician should be able to take a history and perform a physical exam, recommend appropriate studies, and come up with a differential diagnosis. A disposition based on evaluating this information in conjunction with training and experience can then be arrived at. I am an orthopedist, not a "hack" or an "ogre" and I generally refer to physiatrists, both md and osteopaths I trust, not cynics.
Back Pain answer. Get a thorough evaluation by a reputable chronic pain specialist (not a surgeon as the first line of attack). Find out specifically what is causing the pain then treat it. Do not mask the pain with medications since that will not enhance your life, but rather treat the root cause with as minimally invasive treatment as is possible. Start the journey today.
See Osteopath. Chronic back pain in late teenager absent mechanical injury suggests spondylolisthesis. If extreme sports enthusiast then sacroiliac joint disorder is of concern & commonly sciatica to thigh & knee associated. An MRI can rule out lumbar spinal nerve root irritation. Degenerative disk disease (ddd) diagnosis would be incorrect & abborhent. Osteopath or physiatrist can diagnose. Avoid orthopedists!