No but it may be needed for insurance reimbursement.
In many cases it does, although it depends on your policy and illness. A doctor's referral may qualify your physical therapy for coverage as well.
Your therapist has special training to make sure your therapy is comfortable at all times. You may be asked to stretch, exercise or move in ways that are difficult but you should not experience pain. Recovering after a long period of inactivity may seem physically demanding, but the rewards are improved strength, flexibility and movement.
Wear comfortable clothing that will allow movement, stretching or the application of ice or heat packs.
Each appointment lasts about an hour. You may have one or more sessions depending on your illness or injury. Treatment may continue for several weeks and you will also have exercises or other therapies which you should do at home.