Can the use of crutches cause lower back pain, i've been using them for a knee injury about 2 months?

Low back pain is mostly caused by injury to a muscle (strain) or ligament (sprain). Common causes include improper lifting, poor posture, lack of regular exercise, fracture, ruptured disk, or arthritis. You should use alternating hot pads/cold pads, and pain relievers such as acetaminophen for relief. Rest the area for several weeks. Crutches can make the pain worse due to using back muscles.