3/3
In ALS, the muscle shrinks, also after prolonged disuse. Since the motor nerve in the brain is destroyed, the nerve doesn’t order the muscle to contract. So the patient sits in a chair, is lifted by caregivers to the toilet, and then is lifted to bed. The muscle never gets the signal to contract, so there is no attempted movement. The muscle itself is NOT failing, so it is not pushing against anything, so it doesn’t feel pain. So the answer to your question, in the case of atrophy due to ALS, the patient feels just fine—no pain, no nothing. He looks at his muscle and thinks, “I feel normal, but I can’t walk!”