There are several possible reasons for this. Generalized back pain can occur just related to muscle fatigue. In adult-onset scoliosis, there are disc degeneration, bone spur formation, and facet (spinal) joint changes that contribute to muscle imbalance and deformity. The imbalance of muscle pull from spinal deformity can cause pain.
Often in older adults, there are other problems at the same time that make the symptoms of scoliosis worse. For example, spinal stenosis (narrowing of the spinal canal) is a common cause of back and leg pain in this age group. When you combine the changes caused by scoliosis along with the changes from spinal stenosis, the symptoms of back and leg pain can escalate.
Another problem encountered by this age group is peripheral vascular disease (PVD). Arteries and veins get clogged up with atherosclerotic plaques resulting in diminished blood supply to the legs. This is another potential cause of leg pain with walking.
Fragile bones from osteoporosis is common in postmenopausal women. This condition affects men, too but about 10 years later. Insuffiency or vertebral compression fractures are a potential source of pain in an older adult with scoliosis.
If your mother hasn’t been evaluated by her physician, now would be a good time to update her medical exam and find out what’s going on. There are many ways to treat this problem and bring about pain relief and improved function.