Amyotrophic Lateral Sclerosis (ALS) is a disease that affects motor nerves, and pain is felt by sensory nerves. The disease does not cause an individual to experience pain, however the effects ALS has on the body does cause pain. For example, joint pain can develop when limbs become weak. When a person’s limbs grow weak, they have a tendency to not use those limbs anymore. The limb will grow stiff and cause pain in the body.