For many years, the medical community did not support the idea that pain could be caused by the effects of MS, but physicians today recognize that pain is a common symptom. Surveys for patient pain indicate that the most common pain syndromes experienced in MS are: continuous burning in extremities; headache; back pain; and painful tonic spasms. Weakness on one side of the body will cause someone to favor the other side and develop stiff joints; muscles can become twisted and cause the body to be unbalanced, frequently leading to muscle and joint pain. The same is true for spasticity (muscle stiffness) and spasms, as well as poor posture, with pain often occurring in the lower back. Even medications can sometimes cause painful side effects such as injection-site reactions, steroid-induced osteoporosis, and degenerative joint disease.