Hello,, here are some of the common causes for backache - Years of poor posture, improper lifting and carrying of heavy objects, being overweight, which puts excess strain on the back and knees, a congenital condition such as curvature of the spine, traumatic injury wearing, wearing high heels, sleeping on a poor mattress, Sometimes no obvious physical cause, ordinary aging of the spine (degenerative changes) If you are feeling better after exercise, then it is actually good,,, try to practice and make a habit of doing exercise daily morning and evening, it not only good for your back but to your whole body. A physiotherapist will teach you the good exercises. If you still get backache then visit orthopedician he will treat your backache.